diff --git a/protected/java/test/org/broadinstitute/sting/gatk/walkers/genotyper/UnifiedGenotyperGeneralPloidyIntegrationTest.java b/protected/java/test/org/broadinstitute/sting/gatk/walkers/genotyper/UnifiedGenotyperGeneralPloidyIntegrationTest.java
index 5cdc15e5e..54dcbb395 100644
--- a/protected/java/test/org/broadinstitute/sting/gatk/walkers/genotyper/UnifiedGenotyperGeneralPloidyIntegrationTest.java
+++ b/protected/java/test/org/broadinstitute/sting/gatk/walkers/genotyper/UnifiedGenotyperGeneralPloidyIntegrationTest.java
@@ -55,36 +55,36 @@ public class UnifiedGenotyperGeneralPloidyIntegrationTest extends WalkerTest {
 
     @Test(enabled = true)
     public void testSNP_ACS_Pools() {
-        PC_LSV_Test_short(" -maxAltAlleles 1 -ploidy 6 -out_mode EMIT_ALL_CONFIDENT_SITES","LSV_SNP_ACS","SNP","651469eeacdb3ab9e2690cfb71f6a634");
+        PC_LSV_Test_short(" -maxAltAlleles 1 -ploidy 6 -out_mode EMIT_ALL_CONFIDENT_SITES","LSV_SNP_ACS","SNP","df0e67c975ef74d593f1c704daab1705");
     }
 
     @Test(enabled = true)
     public void testBOTH_GGA_Pools() {
-        PC_LSV_Test(String.format(" -maxAltAlleles 2 -ploidy 24 -gt_mode GENOTYPE_GIVEN_ALLELES -out_mode EMIT_ALL_SITES -alleles %s",LSV_ALLELES),"LSV_BOTH_GGA","BOTH","be7dc20bdb5f200d189706bcf1aeb7ee");
+        PC_LSV_Test(String.format(" -maxAltAlleles 2 -ploidy 24 -gt_mode GENOTYPE_GIVEN_ALLELES -out_mode EMIT_ALL_SITES -alleles %s",LSV_ALLELES),"LSV_BOTH_GGA","BOTH","d1c113a17e36762d27eb27fd12528e52");
     }
 
     @Test(enabled = true)
     public void testINDEL_GGA_Pools() {
-        PC_LSV_Test(String.format(" -maxAltAlleles 1 -ploidy 24 -gt_mode GENOTYPE_GIVEN_ALLELES  -out_mode EMIT_ALL_SITES -alleles %s",LSV_ALLELES),"LSV_INDEL_GGA","INDEL","25e5ea86d87b7d7ddaad834a6ed7481d");
+        PC_LSV_Test(String.format(" -maxAltAlleles 1 -ploidy 24 -gt_mode GENOTYPE_GIVEN_ALLELES  -out_mode EMIT_ALL_SITES -alleles %s",LSV_ALLELES),"LSV_INDEL_GGA","INDEL","ab043eed87fadbe5761a55a4912b19ac");
     }
 
     @Test(enabled = true)
     public void testINDEL_maxAltAlleles2_ploidy3_Pools_noRef() {
-        PC_LSV_Test_NoRef(" -maxAltAlleles 2 -ploidy 3","LSV_INDEL_DISC_NOREF_p3","INDEL","cdbf268d282e57189a88fb83f0e1fd72");
+        PC_LSV_Test_NoRef(" -maxAltAlleles 2 -ploidy 3","LSV_INDEL_DISC_NOREF_p3","INDEL","95d48e0680019d5406ff9adb8f2ff3ca");
     }
 
     @Test(enabled = true)
     public void testINDEL_maxAltAlleles2_ploidy1_Pools_noRef() {
-        PC_LSV_Test_NoRef(" -maxAltAlleles 2 -ploidy 1","LSV_INDEL_DISC_NOREF_p1","INDEL","2ed40925cd112c1a45470d215b7ec4b3");
+        PC_LSV_Test_NoRef(" -maxAltAlleles 2 -ploidy 1","LSV_INDEL_DISC_NOREF_p1","INDEL","8a4ddd64c4e9c42b4a8622582fcfa9c9");
     }
 
     @Test(enabled = true)
     public void testMT_SNP_DISCOVERY_sp4() {
-         PC_MT_Test(CEUTRIO_BAM, " -maxAltAlleles 1 -ploidy 8", "MT_SNP_DISCOVERY_sp4","33695a998bcc906cabcc758727004387");
+         PC_MT_Test(CEUTRIO_BAM, " -maxAltAlleles 1 -ploidy 8", "MT_SNP_DISCOVERY_sp4","3fc6f4d458313616727c60e49c0e852b");
     }
 
     @Test(enabled = true)
     public void testMT_SNP_GGA_sp10() {
-        PC_MT_Test(CEUTRIO_BAM, String.format(" -maxAltAlleles 1 -ploidy 20 -gt_mode GENOTYPE_GIVEN_ALLELES  -out_mode EMIT_ALL_SITES -alleles %s",NA12891_CALLS), "MT_SNP_GGA_sp10", "b2725242114bf9cc9bca14679705ba40");
+        PC_MT_Test(CEUTRIO_BAM, String.format(" -maxAltAlleles 1 -ploidy 20 -gt_mode GENOTYPE_GIVEN_ALLELES  -out_mode EMIT_ALL_SITES -alleles %s",NA12891_CALLS), "MT_SNP_GGA_sp10", "1bebbc0f28bff6fd64736ccca8839df8");
     }
 }
diff --git a/protected/java/test/org/broadinstitute/sting/gatk/walkers/genotyper/UnifiedGenotyperIntegrationTest.java b/protected/java/test/org/broadinstitute/sting/gatk/walkers/genotyper/UnifiedGenotyperIntegrationTest.java
index e40a7ed38..8aaeccc55 100755
--- a/protected/java/test/org/broadinstitute/sting/gatk/walkers/genotyper/UnifiedGenotyperIntegrationTest.java
+++ b/protected/java/test/org/broadinstitute/sting/gatk/walkers/genotyper/UnifiedGenotyperIntegrationTest.java
@@ -30,7 +30,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testMultiSamplePilot1() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 baseCommand + " -I " + validationDataLocation + "low_coverage_CEU.chr1.10k-11k.bam -o %s -L 1:10,022,000-10,025,000", 1,
-                Arrays.asList("2ba9af34d2a4d55caf152265a30ead46"));
+                Arrays.asList("847605f4efafef89529fe0e496315edd"));
         executeTest("test MultiSample Pilot1", spec);
     }
 
@@ -38,7 +38,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testWithAllelesPassedIn1() {
         WalkerTest.WalkerTestSpec spec1 = new WalkerTest.WalkerTestSpec(
                 baseCommand + " --genotyping_mode GENOTYPE_GIVEN_ALLELES -alleles " + privateTestDir + "allelesForUG.vcf -I " + validationDataLocation + "pilot2_daughters.chr20.10k-11k.bam -o %s -L 20:10,000,000-10,025,000", 1,
-                Arrays.asList("0630c35c070d7a7e0cf22b3cce797f22"));
+                Arrays.asList("5b31b811072a4df04524e13604015f9b"));
         executeTest("test MultiSample Pilot2 with alleles passed in", spec1);
     }
 
@@ -46,7 +46,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testWithAllelesPassedIn2() {
         WalkerTest.WalkerTestSpec spec2 = new WalkerTest.WalkerTestSpec(
                 baseCommand + " --output_mode EMIT_ALL_SITES --genotyping_mode GENOTYPE_GIVEN_ALLELES -alleles " + privateTestDir + "allelesForUG.vcf -I " + validationDataLocation + "pilot2_daughters.chr20.10k-11k.bam -o %s -L 20:10,000,000-10,025,000", 1,
-                Arrays.asList("5857dcb4e6a8422ae0813e42d433b122"));
+                Arrays.asList("d9992e55381afb43742cc9b30fcd7538"));
         executeTest("test MultiSample Pilot2 with alleles passed in and emitting all sites", spec2);
     }
 
@@ -54,7 +54,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testSingleSamplePilot2() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 baseCommand + " -I " + validationDataLocation + "NA12878.1kg.p2.chr1_10mb_11_mb.SLX.bam -o %s -L 1:10,000,000-10,100,000", 1,
-                Arrays.asList("489deda5d3276545364a06b7385f8bd9"));
+                Arrays.asList("dff4412a074940d26994f9552476b209"));
         executeTest("test SingleSample Pilot2", spec);
     }
 
@@ -62,7 +62,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testMultipleSNPAlleles() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 "-T UnifiedGenotyper -R " + b37KGReference + " --no_cmdline_in_header -glm BOTH --dbsnp " + b37dbSNP129 + " -I " + privateTestDir + "multiallelic.snps.bam -o %s -L " + privateTestDir + "multiallelic.snps.intervals", 1,
-                Arrays.asList("595ba44c75d08dab98df222b8e61ab70"));
+                Arrays.asList("b41b95aaa2c453c9b75b3b29a9c2718e"));
         executeTest("test Multiple SNP alleles", spec);
     }
 
@@ -70,7 +70,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testBadRead() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 "-T UnifiedGenotyper -R " + b37KGReference + " --no_cmdline_in_header -glm BOTH -I " + privateTestDir + "badRead.test.bam -o %s -L 1:22753424-22753464", 1,
-                Arrays.asList("360f9795facdaa14c0cb4b05207142e4"));
+                Arrays.asList("d915535c1458733f09f82670092fcab6"));
         executeTest("test bad read", spec);
     }
 
@@ -78,7 +78,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testReverseTrim() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 "-T UnifiedGenotyper -R " + b37KGReference + " --no_cmdline_in_header -glm INDEL -I " + validationDataLocation + "CEUTrio.HiSeq.b37.chr20.10_11mb.bam -o %s -L 20:10289124 -L 20:10090289", 1,
-                Arrays.asList("4b4a62429f8eac1e2f27ba5e2edea9e5"));
+                Arrays.asList("44e9f6cf11b4efecb454cd3de8de9877"));
         executeTest("test reverse trim", spec);
     }
 
@@ -86,7 +86,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testMismatchedPLs() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 "-T UnifiedGenotyper -R " + b37KGReference + " --no_cmdline_in_header -glm INDEL -I " + privateTestDir + "mismatchedPLs.bam -o %s -L 1:24020341", 1,
-                Arrays.asList("cc892c91a93dbd8dbdf645803f35a0ee"));
+                Arrays.asList("935ee705ffe8cc6bf1d9efcceea271c8"));
         executeTest("test mismatched PLs", spec);
     }
 
@@ -96,7 +96,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     //
     // --------------------------------------------------------------------------------------------------------------
 
-    private final static String COMPRESSED_OUTPUT_MD5 = "3fc7d2681ff753e2d68605d7cf8b63e3";
+    private final static String COMPRESSED_OUTPUT_MD5 = "e6e33f0ebabab027eabed51fe9a08da9";
 
     @Test
     public void testCompressedOutput() {
@@ -149,7 +149,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testMinBaseQualityScore() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 baseCommand + " -I " + validationDataLocation + "NA12878.1kg.p2.chr1_10mb_11_mb.SLX.bam -o %s -L 1:10,000,000-10,010,000 --min_base_quality_score 26", 1,
-                Arrays.asList("04dc83d7dfb42b8cada91647bd9f32f1"));
+                Arrays.asList("6ee6537e9ebc1bfc7c6cf8f04b1582ff"));
         executeTest("test min_base_quality_score 26", spec);
     }
 
@@ -157,7 +157,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testSLOD() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 "-T UnifiedGenotyper -R " + b36KGReference + " --computeSLOD --no_cmdline_in_header -glm BOTH --dbsnp " + b36dbSNP129 + " -I " + validationDataLocation + "NA12878.1kg.p2.chr1_10mb_11_mb.SLX.bam -o %s -L 1:10,000,000-10,010,000", 1,
-                Arrays.asList("4429a665a1048f958db3c204297cdb9f"));
+                Arrays.asList("55760482335497086458b09e415ecf54"));
         executeTest("test SLOD", spec);
     }
 
@@ -165,7 +165,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testNDA() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 baseCommand + " --annotateNDA -I " + validationDataLocation + "NA12878.1kg.p2.chr1_10mb_11_mb.SLX.bam -o %s -L 1:10,000,000-10,010,000", 1,
-                Arrays.asList("f063e3573c513eaa9ce7d7df22143362"));
+                Arrays.asList("938e888a40182878be4c3cc4859adb69"));
         executeTest("test NDA", spec);
     }
 
@@ -173,7 +173,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testCompTrack() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 "-T UnifiedGenotyper -R " + b36KGReference + " --no_cmdline_in_header -glm BOTH -comp:FOO " + b36dbSNP129 + " -I " + validationDataLocation + "NA12878.1kg.p2.chr1_10mb_11_mb.SLX.bam -o %s -L 1:10,000,000-10,010,000", 1,
-                Arrays.asList("d76e93e2676354dde832f08a508c6f88"));
+                Arrays.asList("7dc186d420487e4e156a24ec8dea0951"));
         executeTest("test using comp track", spec);
     }
 
@@ -187,17 +187,17 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
 
     @Test
     public void testOutputParameterSitesOnly() {
-        testOutputParameters("-sites_only", "1a65172b9bd7a2023d48bc758747b34a");
+        testOutputParameters("-sites_only", "f99c7471127a6fb6f72e136bc873b2c9");
     }
 
     @Test
     public void testOutputParameterAllConfident() {
-        testOutputParameters("--output_mode EMIT_ALL_CONFIDENT_SITES", "3f1fa34d8440f6f21654ce60c0ba8f28");
+        testOutputParameters("--output_mode EMIT_ALL_CONFIDENT_SITES", "9dbc9389db39cf9697e93e0bf529314f");
     }
 
     @Test
     public void testOutputParameterAllSites() {
-        testOutputParameters("--output_mode EMIT_ALL_SITES", "f240434b4d3c234f6f9e349e9ec05f4e");
+        testOutputParameters("--output_mode EMIT_ALL_SITES", "8b26088a035e579c4afd3b46737291e4");
     }
 
     private void testOutputParameters(final String args, final String md5) {
@@ -211,7 +211,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testConfidence() {
         WalkerTest.WalkerTestSpec spec1 = new WalkerTest.WalkerTestSpec(
                 baseCommand + " -I " + validationDataLocation + "NA12878.1kg.p2.chr1_10mb_11_mb.SLX.bam -o %s -L 1:10,000,000-10,010,000 -stand_call_conf 10 ", 1,
-                Arrays.asList("aec378bed312b3557c6dd7ec740c8091"));
+                Arrays.asList("4af83a883ecc03a23b0aa6dd4b8f1ceb"));
         executeTest("test confidence 1", spec1);
     }
 
@@ -222,12 +222,12 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     // --------------------------------------------------------------------------------------------------------------
     @Test
     public void testHeterozyosity1() {
-        testHeterozosity( 0.01, "5da6b24033a6b02f466836443d49560e" );
+        testHeterozosity( 0.01, "bdc8760d7ae1e01c0510b12c1e6fcfa3" );
     }
 
     @Test
     public void testHeterozyosity2() {
-        testHeterozosity( 1.0 / 1850, "1f284c4af967a3c26687164f9441fb16" );
+        testHeterozosity( 1.0 / 1850, "f508f06a47305e11e62776615cb14fe3" );
     }
 
     private void testHeterozosity(final double arg, final String md5) {
@@ -251,7 +251,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
                         " -o %s" +
                         " -L 1:10,000,000-10,100,000",
                 1,
-                Arrays.asList("cff553c53de970f64051ed5711407038"));
+                Arrays.asList("13d91059f58fb50a07a6a34b9438a45b"));
 
         executeTest(String.format("test multiple technologies"), spec);
     }
@@ -270,7 +270,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
                         " -L 1:10,000,000-10,100,000" +
                         " -baq CALCULATE_AS_NECESSARY",
                 1,
-                Arrays.asList("f960a91963e614a6c8d8cda57836df24"));
+                Arrays.asList("07d8b77a5f6697f3a47a4f1efb0dcf50"));
 
         executeTest(String.format("test calling with BAQ"), spec);
     }
@@ -289,7 +289,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
                         " -o %s" +
                         " -L 1:10,000,000-10,500,000",
                 1,
-                Arrays.asList("46a6d24c82ebb99d305462960fa09b7c"));
+                Arrays.asList("0f026d2e568172cf32813cc54ea7ba23"));
 
         executeTest(String.format("test indel caller in SLX"), spec);
     }
@@ -304,7 +304,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
                         " -minIndelCnt 1" +
                         " -L 1:10,000,000-10,100,000",
                 1,
-                Arrays.asList("2be25321bbc6a963dba7ecba5dd76802"));
+                Arrays.asList("e7ad858e9d6617534761918561f3ed4c"));
 
         executeTest(String.format("test indel caller in SLX with low min allele count"), spec);
     }
@@ -317,7 +317,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
                          " -o %s" +
                          " -L 1:10,000,000-10,500,000",
                  1,
-                 Arrays.asList("d6b2657cd5a4a949968cdab50efce515"));
+                 Arrays.asList("39c7a813fd6ee82d3604f2a868b35b2a"));
 
          executeTest(String.format("test indel calling, multiple technologies"), spec);
      }
@@ -327,7 +327,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 baseCommandIndels + " --genotyping_mode GENOTYPE_GIVEN_ALLELES -alleles " + privateTestDir + "indelAllelesForUG.vcf -I " + validationDataLocation +
                         "pilot2_daughters.chr20.10k-11k.bam -o %s -L 20:10,000,000-10,100,000", 1,
-                Arrays.asList("9cff66a321284c362f393bc4db21f756"));
+                Arrays.asList("9430fe36789a791fcff6162f768ae563"));
         executeTest("test MultiSample Pilot2 indels with alleles passed in", spec);
     }
 
@@ -337,7 +337,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
                 baseCommandIndels + " --output_mode EMIT_ALL_SITES --genotyping_mode GENOTYPE_GIVEN_ALLELES -alleles "
                         + privateTestDir + "indelAllelesForUG.vcf -I " + validationDataLocation +
                         "pilot2_daughters.chr20.10k-11k.bam -o %s -L 20:10,000,000-10,100,000", 1,
-                Arrays.asList("90c8cfcf65152534c16ed81104fc3bcd"));
+                Arrays.asList("8d8dbf483526b0b309f5728619a74a86"));
         executeTest("test MultiSample Pilot2 indels with alleles passed in and emitting all sites", spec);
     }
 
@@ -345,13 +345,13 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testMultiSampleIndels1() {
         WalkerTest.WalkerTestSpec spec1 = new WalkerTest.WalkerTestSpec(
                 baseCommandIndels + " -I " + validationDataLocation + "low_coverage_CEU.chr1.10k-11k.bam -o %s -L 1:10450700-10551000", 1,
-                Arrays.asList("457b8f899cf1665de61e75084dbb79d0"));
+                Arrays.asList("5667a699a3a13474f2d1cd2d6b01cd5b"));
         List<File> result = executeTest("test MultiSample Pilot1 CEU indels", spec1).getFirst();
 
         WalkerTest.WalkerTestSpec spec2 = new WalkerTest.WalkerTestSpec(
                 baseCommandIndels + " --genotyping_mode GENOTYPE_GIVEN_ALLELES -alleles " + result.get(0).getAbsolutePath() + " -I " + validationDataLocation +
                         "low_coverage_CEU.chr1.10k-11k.bam -o %s -L 1:10450700-10551000", 1,
-                Arrays.asList("a13fe7aa3b9e8e091b3cf3442a056ec1"));
+                Arrays.asList("b6c1d5cd28ff584c5f5037afef4e883a"));
         executeTest("test MultiSample Pilot1 CEU indels using GENOTYPE_GIVEN_ALLELES", spec2);
     }
 
@@ -361,7 +361,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 baseCommandIndelsb37 + " --genotyping_mode GENOTYPE_GIVEN_ALLELES -out_mode EMIT_ALL_SITES -alleles " + privateTestDir + vcf + " -I " + validationDataLocation +
                         "NA12878.HiSeq.WGS.bwa.cleaned.recal.hg19.20.bam -o %s -L " + validationDataLocation + vcf, 1,
-                Arrays.asList("d075ad318739c8c56bdce857da1e48b9"));
+                Arrays.asList("d76eacc4021b78ccc0a9026162e814a7"));
         executeTest("test GENOTYPE_GIVEN_ALLELES with no evidence in reads", spec);
     }
 
@@ -373,7 +373,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
                         " -o %s" +
                         " -L 20:10,000,000-10,100,000",
                 1,
-                Arrays.asList("91c632ab17a1dd89ed19ebb20324f905"));
+                Arrays.asList("1e0d2c15546c3b0959b00ffb75488b56"));
 
         executeTest(String.format("test UG with base indel quality scores"), spec);
     }
@@ -407,7 +407,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testMinIndelFraction0() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 assessMinIndelFraction + " -minIndelFrac 0.0", 1,
-                Arrays.asList("1d80e135d611fe19e1fb1882aa588a73"));
+                Arrays.asList("db3026c49a3de7a5cb9a3d77635d0706"));
         executeTest("test minIndelFraction 0.0", spec);
     }
 
@@ -415,7 +415,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testMinIndelFraction25() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 assessMinIndelFraction + " -minIndelFrac 0.25", 1,
-                Arrays.asList("752139616752902fca13c312d8fe5e22"));
+                Arrays.asList("7ab8e5ee15ab98d6756b0eea0f4d3798"));
         executeTest("test minIndelFraction 0.25", spec);
     }
 
@@ -423,7 +423,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testMinIndelFraction100() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 assessMinIndelFraction + " -minIndelFrac 1", 1,
-                Arrays.asList("d66b9decf26e1704abda1a919ac149cd"));
+                Arrays.asList("3f07efb768e08650a7ce333edd4f9a52"));
         executeTest("test minIndelFraction 1.0", spec);
     }
 
@@ -437,7 +437,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testNsInCigar() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 "-T UnifiedGenotyper -R " + b37KGReference + " --no_cmdline_in_header -I " + privateTestDir + "testWithNs.bam -o %s -L 8:141813600-141813700 -out_mode EMIT_ALL_SITES", 1,
-                Arrays.asList("b62ba9777efc05af4c36e2d4ce3ee67c"));
+                Arrays.asList("4d36969d4f8f1094f1fb6e7e085c19f6"));
         executeTest("test calling on reads with Ns in CIGAR", spec);
     }
 
@@ -451,18 +451,18 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testReducedBam() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 "-T UnifiedGenotyper -R " + b37KGReference + " --no_cmdline_in_header -I " + privateTestDir + "bamExample.ReducedRead.ADAnnotation.bam -o %s -L 1:67,225,396-67,288,518", 1,
-                Arrays.asList("f72ecd00b2913f63788faa7dabb1d102"));
+                Arrays.asList("092e42a712afb660ec79ff11c55933e2"));
         executeTest("test calling on a ReducedRead BAM", spec);
     }
 
     @Test
     public void testReducedBamSNPs() {
-        testReducedCalling("SNP", "f059743858004ceee325f2a7761a2362");
+        testReducedCalling("SNP", "c0de74ab8f4f14eb3a2c5d55c200ac5f");
     }
 
     @Test
     public void testReducedBamINDELs() {
-        testReducedCalling("INDEL", "04845ba1ec7d8d8b0eab2ca6bdb9c1a6");
+        testReducedCalling("INDEL", "1c9aaf65ffaa12bb766855265a1c3f8e");
     }
 
 
@@ -483,7 +483,7 @@ public class UnifiedGenotyperIntegrationTest extends WalkerTest {
     public void testContaminationDownsampling() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 baseCommand + " -I " + validationDataLocation + "NA12878.1kg.p2.chr1_10mb_11_mb.SLX.bam -o %s -L 1:10,000,000-10,010,000 --contamination_fraction_to_filter 0.20", 1,
-                Arrays.asList("b500ad5959bce69f888a2fac024647e5"));
+                Arrays.asList("1f9071466fc40f4c6a0f58ac8e9135fb"));
         executeTest("test contamination_percentage_to_filter 0.20", spec);
     }
 
diff --git a/protected/java/test/org/broadinstitute/sting/gatk/walkers/haplotypecaller/HaplotypeCallerIntegrationTest.java b/protected/java/test/org/broadinstitute/sting/gatk/walkers/haplotypecaller/HaplotypeCallerIntegrationTest.java
index bb9efe15d..1683044f0 100644
--- a/protected/java/test/org/broadinstitute/sting/gatk/walkers/haplotypecaller/HaplotypeCallerIntegrationTest.java
+++ b/protected/java/test/org/broadinstitute/sting/gatk/walkers/haplotypecaller/HaplotypeCallerIntegrationTest.java
@@ -21,19 +21,19 @@ public class HaplotypeCallerIntegrationTest extends WalkerTest {
 
     @Test
     public void testHaplotypeCallerMultiSample() {
-        HCTest(CEUTRIO_BAM, "", "7122d4f0ef94c5274aa3047cfebe08ed");
+        HCTest(CEUTRIO_BAM, "", "47fdbe5f01d3ce5e53056eea8c488e45");
     }
 
     @Test
     public void testHaplotypeCallerSingleSample() {
-        HCTest(NA12878_BAM, "", "6cd6e6787521c07a7bae98766fd628ab");
+        HCTest(NA12878_BAM, "", "a2c63f6e6e51a01019bdbd23125bdb15");
     }
 
     // TODO -- add more tests for GGA mode, especially with input alleles that are complex variants and/or not trimmed
     @Test
     public void testHaplotypeCallerMultiSampleGGA() {
         HCTest(CEUTRIO_BAM, "--max_alternate_alleles 3 -gt_mode GENOTYPE_GIVEN_ALLELES -out_mode EMIT_ALL_SITES -alleles " + validationDataLocation + "combined.phase1.chr20.raw.indels.sites.vcf",
-                "44df2a9da4fbd2162ae44c3f2a6ef01f");
+                "54b7cc3da3d8349ff4302f99883ab188");
     }
 
     private void HCTestComplexVariants(String bam, String args, String md5) {
@@ -44,7 +44,7 @@ public class HaplotypeCallerIntegrationTest extends WalkerTest {
 
     @Test
     public void testHaplotypeCallerMultiSampleComplex() {
-        HCTestComplexVariants(privateTestDir + "AFR.complex.variants.bam", "", "4a413eeb7a75cab0ab5370b4c08dcf8e");
+        HCTestComplexVariants(privateTestDir + "AFR.complex.variants.bam", "", "6c0c441b71848c2eea38ab5e2afe1120");
     }
 
     private void HCTestSymbolicVariants(String bam, String args, String md5) {
@@ -55,7 +55,7 @@ public class HaplotypeCallerIntegrationTest extends WalkerTest {
 
     @Test
     public void testHaplotypeCallerSingleSampleSymbolic() {
-        HCTestSymbolicVariants(NA12878_CHR20_BAM, "", "77cf5b5273828dd1605bb23a5aeafcaa");
+        HCTestSymbolicVariants(NA12878_CHR20_BAM, "", "0761ff5cbf279be467833fa6708bf360");
     }
 
     private void HCTestIndelQualityScores(String bam, String args, String md5) {
@@ -66,20 +66,20 @@ public class HaplotypeCallerIntegrationTest extends WalkerTest {
 
     @Test
     public void testHaplotypeCallerSingleSampleIndelQualityScores() {
-        HCTestIndelQualityScores(NA12878_RECALIBRATED_BAM, "", "87ca97f90e74caee35c35616c065821c");
+        HCTestIndelQualityScores(NA12878_RECALIBRATED_BAM, "", "29f1125df5ab27cc937a144ae08ac735");
     }
 
     @Test
     public void HCTestProblematicReadsModifiedInActiveRegions() {
         final String base = String.format("-T HaplotypeCaller -R %s -I %s", REF, privateTestDir + "haplotype-problem-4.bam") + " --no_cmdline_in_header -o %s -minPruning 3 -L 4:49139026-49139965";
-        final WalkerTestSpec spec = new WalkerTestSpec(base, Arrays.asList("3df42d0550b51eb9b55aac61e8b3c452"));
+        final WalkerTestSpec spec = new WalkerTestSpec(base, Arrays.asList("ece627de486aee69d02872891c6cb0ff"));
         executeTest("HCTestProblematicReadsModifiedInActiveRegions: ", spec);
     }
 
     @Test
     public void HCTestStructuralIndels() {
         final String base = String.format("-T HaplotypeCaller -R %s -I %s", REF, privateTestDir + "AFR.structural.indels.bam") + " --no_cmdline_in_header -o %s -minPruning 6 -L 20:8187565-8187800 -L 20:18670537-18670730";
-        final WalkerTestSpec spec = new WalkerTestSpec(base, Arrays.asList("4dbc72b72e3e2d9d812d5a398490e213"));
+        final WalkerTestSpec spec = new WalkerTestSpec(base, Arrays.asList("add0f4f51969b7caeea99005a7ba1aa4"));
         executeTest("HCTestStructuralIndels: ", spec);
     }
 
@@ -93,7 +93,7 @@ public class HaplotypeCallerIntegrationTest extends WalkerTest {
     public void HCTestReducedBam() {
         WalkerTest.WalkerTestSpec spec = new WalkerTest.WalkerTestSpec(
                 "-T HaplotypeCaller -R " + b37KGReference + " --no_cmdline_in_header -I " + privateTestDir + "bamExample.ReducedRead.ADAnnotation.bam -o %s -L 1:67,225,396-67,288,518", 1,
-                Arrays.asList("f8c2745bf71f2659a57494fcaa2c103b"));
+                Arrays.asList("8a400b0c46f41447fcc35a907e34f384"));
         executeTest("HC calling on a ReducedRead BAM", spec);
     }
 }
diff --git a/public/java/src/org/broadinstitute/sting/gatk/GenomeAnalysisEngine.java b/public/java/src/org/broadinstitute/sting/gatk/GenomeAnalysisEngine.java
index bee25dc2f..1187039bb 100755
--- a/public/java/src/org/broadinstitute/sting/gatk/GenomeAnalysisEngine.java
+++ b/public/java/src/org/broadinstitute/sting/gatk/GenomeAnalysisEngine.java
@@ -570,32 +570,11 @@ public class GenomeAnalysisEngine {
             else if(walker instanceof ActiveRegionWalker) {
                 if (readsDataSource.getSortOrder() != SAMFileHeader.SortOrder.coordinate)
                     throw new UserException.MissortedBAM(SAMFileHeader.SortOrder.coordinate, "Active region walkers can only traverse coordinate-sorted data.  Please resort your input BAM file(s) or set the Sort Order tag in the header appropriately.");
-
-                switch(argCollection.activeRegionShardType) {
-                    case LOCUSSHARD:
-                        if(intervals == null)
-                            return readsDataSource.createShardIteratorOverMappedReads(referenceDataSource.getReference().getSequenceDictionary(),new LocusShardBalancer());
-                        else
-                            return readsDataSource.createShardIteratorOverIntervals(((ActiveRegionWalker)walker).extendIntervals(intervals, this.genomeLocParser, this.getReferenceDataSource().getReference()), new LocusShardBalancer());
-                    case READSHARD:
-                        // Use the legacy ReadShardBalancer if legacy downsampling is enabled
-                        ShardBalancer readShardBalancer = downsamplingMethod != null && downsamplingMethod.useLegacyDownsampler ?
-                                new LegacyReadShardBalancer() :
-                                new ReadShardBalancer();
-
-                        if(intervals == null)
-                            return readsDataSource.createShardIteratorOverMappedReads(referenceDataSource.getReference().getSequenceDictionary(), readShardBalancer);
-                        else
-                            return readsDataSource.createShardIteratorOverIntervals(((ActiveRegionWalker)walker).extendIntervals(intervals, this.genomeLocParser, this.getReferenceDataSource().getReference()), readShardBalancer);
-                    case ACTIVEREGIONSHARD:
-                        if(intervals == null)
-                            return readsDataSource.createShardIteratorOverMappedReads(referenceDataSource.getReference().getSequenceDictionary(),new ActiveRegionShardBalancer());
-                        else
-                            return readsDataSource.createShardIteratorOverIntervals(((ActiveRegionWalker)walker).extendIntervals(intervals, this.genomeLocParser, this.getReferenceDataSource().getReference()), new ActiveRegionShardBalancer());
-                    default:
-                        throw new UserException.CommandLineException("Invalid active region shard type.");
-                }
-            }
+                if(intervals == null)
+                    return readsDataSource.createShardIteratorOverMappedReads(referenceDataSource.getReference().getSequenceDictionary(),new LocusShardBalancer());
+                else
+                    return readsDataSource.createShardIteratorOverIntervals(((ActiveRegionWalker)walker).extendIntervals(intervals, this.genomeLocParser, this.getReferenceDataSource().getReference()), new LocusShardBalancer());
+            } 
             else if(walker instanceof ReadWalker || walker instanceof ReadPairWalker || walker instanceof DuplicateWalker) {
                 // Apply special validation to read pair walkers.
                 if(walker instanceof ReadPairWalker) {
diff --git a/public/java/src/org/broadinstitute/sting/gatk/arguments/GATKArgumentCollection.java b/public/java/src/org/broadinstitute/sting/gatk/arguments/GATKArgumentCollection.java
index beaeacc85..d9c7c9008 100755
--- a/public/java/src/org/broadinstitute/sting/gatk/arguments/GATKArgumentCollection.java
+++ b/public/java/src/org/broadinstitute/sting/gatk/arguments/GATKArgumentCollection.java
@@ -37,7 +37,6 @@ import org.broadinstitute.sting.gatk.downsampling.DownsamplingMethod;
 import org.broadinstitute.sting.gatk.phonehome.GATKRunReport;
 import org.broadinstitute.sting.gatk.samples.PedigreeValidationType;
 import org.broadinstitute.sting.utils.QualityUtils;
-import org.broadinstitute.sting.utils.activeregion.ExperimentalActiveRegionShardType;
 import org.broadinstitute.sting.utils.baq.BAQ;
 import org.broadinstitute.sting.utils.interval.IntervalMergingRule;
 import org.broadinstitute.sting.utils.interval.IntervalSetRule;
@@ -449,14 +448,5 @@ public class GATKArgumentCollection {
     @Hidden
     public boolean generateShadowBCF = false;
     // TODO -- remove all code tagged with TODO -- remove me when argument generateShadowBCF is removed
-
-    // --------------------------------------------------------------------------------------------------------------
-    //
-    // Experimental Active Region Traversal modes
-    //
-    // --------------------------------------------------------------------------------------------------------------
-
-    @Argument(fullName = "active_region_traversal_shard_type", shortName = "active_region_traversal_shard_type", doc = "Choose an experimental shard type for active region traversal, instead of the default LocusShard", required = false)
-    public ExperimentalActiveRegionShardType activeRegionShardType = ExperimentalActiveRegionShardType.LOCUSSHARD;
 }
 
diff --git a/public/java/src/org/broadinstitute/sting/gatk/datasources/providers/ActiveRegionShardDataProvider.java b/public/java/src/org/broadinstitute/sting/gatk/datasources/providers/ActiveRegionShardDataProvider.java
deleted file mode 100644
index 55e51f934..000000000
--- a/public/java/src/org/broadinstitute/sting/gatk/datasources/providers/ActiveRegionShardDataProvider.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright (c) 2012, The Broad Institute
- *
- * Permission is hereby granted, free of charge, to any person
- * obtaining a copy of this software and associated documentation
- * files (the "Software"), to deal in the Software without
- * restriction, including without limitation the rights to use,
- * copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following
- * conditions:
- *
- * The above copyright notice and this permission notice shall be
- * included in all copies or substantial portions of the Software.
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
- * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
- * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
- * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
- * OTHER DEALINGS IN THE SOFTWARE.
- */
-
-package org.broadinstitute.sting.gatk.datasources.providers;
-
-import net.sf.picard.reference.IndexedFastaSequenceFile;
-import org.broadinstitute.sting.gatk.ReadProperties;
-import org.broadinstitute.sting.gatk.datasources.reads.Shard;
-import org.broadinstitute.sting.gatk.datasources.rmd.ReferenceOrderedDataSource;
-import org.broadinstitute.sting.gatk.iterators.LocusIterator;
-import org.broadinstitute.sting.gatk.iterators.StingSAMIterator;
-import org.broadinstitute.sting.utils.GenomeLoc;
-import org.broadinstitute.sting.utils.GenomeLocParser;
-
-import java.util.Collection;
-
-/**
- * @author Joel Thibault
- */
-public class ActiveRegionShardDataProvider extends ShardDataProvider {
-    final private ReadShardDataProvider readProvider;
-    final private LocusShardDataProvider locusProvider;
-
-    public ActiveRegionShardDataProvider(Shard shard, ReadProperties sourceInfo, GenomeLocParser genomeLocParser, StingSAMIterator reads, GenomeLoc locus, LocusIterator locusIterator, IndexedFastaSequenceFile reference, Collection<ReferenceOrderedDataSource> rods) {
-        super(shard, genomeLocParser, reference, rods);     // TODO: necessary?
-        readProvider = new ReadShardDataProvider(shard, genomeLocParser, reads, reference, rods);
-        locusProvider = new LocusShardDataProvider(shard, sourceInfo, genomeLocParser, locus,  locusIterator, reference, rods);
-    }
-
-    public ReadShardDataProvider getReadShardDataProvider() {
-        return readProvider;
-    }
-
-    public LocusShardDataProvider getLocusShardDataProvider(LocusIterator iterator) {
-        return locusProvider;
-    }
-}
diff --git a/public/java/src/org/broadinstitute/sting/gatk/datasources/providers/LocusShardDataProvider.java b/public/java/src/org/broadinstitute/sting/gatk/datasources/providers/LocusShardDataProvider.java
index 1607469eb..4888b9f41 100644
--- a/public/java/src/org/broadinstitute/sting/gatk/datasources/providers/LocusShardDataProvider.java
+++ b/public/java/src/org/broadinstitute/sting/gatk/datasources/providers/LocusShardDataProvider.java
@@ -44,22 +44,6 @@ public class LocusShardDataProvider extends ShardDataProvider {
         this.locusIterator = locusIterator;
     }
 
-    /**
-     * Create a data provider based on an input provider
-     * Used only by ExperimentalReadShardTraverseActiveRegions
-     * @param dataProvider
-     * @param sourceInfo
-     * @param genomeLocParser
-     * @param locus
-     * @param locusIterator
-     */
-    public LocusShardDataProvider(ShardDataProvider dataProvider, ReadProperties sourceInfo, GenomeLocParser genomeLocParser, GenomeLoc locus, LocusIterator locusIterator) {
-        super(dataProvider.getShard(),genomeLocParser,dataProvider.getReference(),dataProvider.getReferenceOrderedData());
-        this.sourceInfo = sourceInfo;
-        this.locus = locus;
-        this.locusIterator = locusIterator;
-    }
-
     /**
      * Returns information about the source of the reads.
      * @return Info about the source of the reads.
diff --git a/public/java/src/org/broadinstitute/sting/gatk/datasources/reads/ActiveRegionShard.java b/public/java/src/org/broadinstitute/sting/gatk/datasources/reads/ActiveRegionShard.java
deleted file mode 100755
index 381b193e9..000000000
--- a/public/java/src/org/broadinstitute/sting/gatk/datasources/reads/ActiveRegionShard.java
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * Copyright (c) 2012, The Broad Institute
- *
- * Permission is hereby granted, free of charge, to any person
- * obtaining a copy of this software and associated documentation
- * files (the "Software"), to deal in the Software without
- * restriction, including without limitation the rights to use,
- * copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following
- * conditions:
- *
- * The above copyright notice and this permission notice shall be
- * included in all copies or substantial portions of the Software.
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
- * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
- * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
- * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
- * OTHER DEALINGS IN THE SOFTWARE.
- */
-
-package org.broadinstitute.sting.gatk.datasources.reads;
-
-import net.sf.samtools.SAMFileSpan;
-import org.broadinstitute.sting.utils.GenomeLoc;
-import org.broadinstitute.sting.utils.GenomeLocParser;
-
-import java.util.List;
-import java.util.Map;
-
-/**
- * @author Joel Thibault
- */
-public class ActiveRegionShard extends ReadShard {
-    public ActiveRegionShard(GenomeLocParser parser, SAMDataSource readsDataSource, Map<SAMReaderID,SAMFileSpan> fileSpans, List<GenomeLoc> loci, boolean isUnmapped) {
-        super(parser, readsDataSource, fileSpans, loci, isUnmapped);
-    }
-}
diff --git a/public/java/src/org/broadinstitute/sting/gatk/datasources/reads/ActiveRegionShardBalancer.java b/public/java/src/org/broadinstitute/sting/gatk/datasources/reads/ActiveRegionShardBalancer.java
deleted file mode 100644
index 338dd1bdf..000000000
--- a/public/java/src/org/broadinstitute/sting/gatk/datasources/reads/ActiveRegionShardBalancer.java
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Copyright (c) 2012, The Broad Institute
- *
- * Permission is hereby granted, free of charge, to any person
- * obtaining a copy of this software and associated documentation
- * files (the "Software"), to deal in the Software without
- * restriction, including without limitation the rights to use,
- * copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following
- * conditions:
- *
- * The above copyright notice and this permission notice shall be
- * included in all copies or substantial portions of the Software.
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
- * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
- * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
- * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
- * OTHER DEALINGS IN THE SOFTWARE.
- */
-
-package org.broadinstitute.sting.gatk.datasources.reads;
-
-/**
- * @author Joel Thibault
- */
-public class ActiveRegionShardBalancer extends ReadShardBalancer {
-    // TODO ?
-}
diff --git a/public/java/src/org/broadinstitute/sting/gatk/datasources/reads/Shard.java b/public/java/src/org/broadinstitute/sting/gatk/datasources/reads/Shard.java
index 314156af6..e22a7a54d 100644
--- a/public/java/src/org/broadinstitute/sting/gatk/datasources/reads/Shard.java
+++ b/public/java/src/org/broadinstitute/sting/gatk/datasources/reads/Shard.java
@@ -40,9 +40,7 @@ import java.util.Map;
  */
 public abstract class Shard implements HasGenomeLocation {
     public enum ShardType {
-        READ,
-        LOCUS,
-        ACTIVEREGION        // Used only by ExperimentalActiveRegionShardTraverseActiveRegions
+        READ, LOCUS
     }
 
     protected final GenomeLocParser parser; // incredibly annoying!
diff --git a/public/java/src/org/broadinstitute/sting/gatk/executive/LinearMicroScheduler.java b/public/java/src/org/broadinstitute/sting/gatk/executive/LinearMicroScheduler.java
index 44f9978a6..f3c1ae91c 100644
--- a/public/java/src/org/broadinstitute/sting/gatk/executive/LinearMicroScheduler.java
+++ b/public/java/src/org/broadinstitute/sting/gatk/executive/LinearMicroScheduler.java
@@ -2,7 +2,6 @@ package org.broadinstitute.sting.gatk.executive;
 
 import net.sf.picard.reference.IndexedFastaSequenceFile;
 import org.broadinstitute.sting.gatk.GenomeAnalysisEngine;
-import org.broadinstitute.sting.gatk.datasources.providers.ActiveRegionShardDataProvider;
 import org.broadinstitute.sting.gatk.datasources.providers.LocusShardDataProvider;
 import org.broadinstitute.sting.gatk.datasources.providers.ReadShardDataProvider;
 import org.broadinstitute.sting.gatk.datasources.providers.ShardDataProvider;
@@ -12,8 +11,6 @@ import org.broadinstitute.sting.gatk.datasources.rmd.ReferenceOrderedDataSource;
 import org.broadinstitute.sting.gatk.io.DirectOutputTracker;
 import org.broadinstitute.sting.gatk.io.OutputTracker;
 import org.broadinstitute.sting.gatk.resourcemanagement.ThreadAllocation;
-import org.broadinstitute.sting.gatk.traversals.ExperimentalActiveRegionShardTraverseActiveRegions;
-import org.broadinstitute.sting.gatk.traversals.ExperimentalReadShardTraverseActiveRegions;
 import org.broadinstitute.sting.gatk.traversals.TraversalEngine;
 import org.broadinstitute.sting.gatk.traversals.TraverseActiveRegions;
 import org.broadinstitute.sting.gatk.walkers.Walker;
@@ -81,18 +78,6 @@ public class LinearMicroScheduler extends MicroScheduler {
                 }
                 windowMaker.close();
             }
-            else if(shard.getShardType() == Shard.ShardType.ACTIVEREGION) {
-                WindowMaker windowMaker = new WindowMaker(shard, engine.getGenomeLocParser(),
-                        getReadIterator(shard), shard.getGenomeLocs(), SampleUtils.getSAMFileSamples(engine));
-                for(WindowMaker.WindowMakerIterator iterator: windowMaker) {
-                    ShardDataProvider dataProvider = new ActiveRegionShardDataProvider(shard,iterator.getSourceInfo(),engine.getGenomeLocParser(),getReadIterator(shard),iterator.getLocus(),iterator,reference,rods);
-                    Object result = traversalEngine.traverse(walker, dataProvider, accumulator.getReduceInit());
-                    accumulator.accumulate(dataProvider,result);
-                    dataProvider.close();
-                    if ( walker.isDone() ) break;
-                }
-                windowMaker.close();
-            }
             else {
                 ShardDataProvider dataProvider = new ReadShardDataProvider(shard,engine.getGenomeLocParser(),getReadIterator(shard),reference,rods);
                 Object result = traversalEngine.traverse(walker, dataProvider, accumulator.getReduceInit());
@@ -108,14 +93,6 @@ public class LinearMicroScheduler extends MicroScheduler {
             final Object result = ((TraverseActiveRegions) traversalEngine).endTraversal(walker, accumulator.getReduceInit());
             accumulator.accumulate(null, result); // Assumes only used with StandardAccumulator
         }
-        else if( traversalEngine instanceof ExperimentalReadShardTraverseActiveRegions ) {
-            final Object result = ((ExperimentalReadShardTraverseActiveRegions) traversalEngine).endTraversal(walker, accumulator.getReduceInit());
-            accumulator.accumulate(null, result); // Assumes only used with StandardAccumulator
-        }
-        else if( traversalEngine instanceof ExperimentalActiveRegionShardTraverseActiveRegions) {
-            final Object result = ((ExperimentalActiveRegionShardTraverseActiveRegions) traversalEngine).endTraversal(walker, accumulator.getReduceInit());
-            accumulator.accumulate(null, result); // Assumes only used with StandardAccumulator
-        }
                 
         Object result = accumulator.finishTraversal();
 
diff --git a/public/java/src/org/broadinstitute/sting/gatk/executive/MicroScheduler.java b/public/java/src/org/broadinstitute/sting/gatk/executive/MicroScheduler.java
index 13c11def6..f8aec1489 100755
--- a/public/java/src/org/broadinstitute/sting/gatk/executive/MicroScheduler.java
+++ b/public/java/src/org/broadinstitute/sting/gatk/executive/MicroScheduler.java
@@ -41,7 +41,6 @@ import org.broadinstitute.sting.gatk.traversals.*;
 import org.broadinstitute.sting.gatk.walkers.*;
 import org.broadinstitute.sting.utils.AutoFormattingTime;
 import org.broadinstitute.sting.utils.MathUtils;
-import org.broadinstitute.sting.utils.activeregion.ExperimentalActiveRegionShardType;
 import org.broadinstitute.sting.utils.exceptions.ReviewedStingException;
 import org.broadinstitute.sting.utils.exceptions.UserException;
 import org.broadinstitute.sting.utils.progressmeter.ProgressMeter;
@@ -246,12 +245,7 @@ public abstract class MicroScheduler implements MicroSchedulerMBean {
         } else if (walker instanceof ReadPairWalker) {
             return new TraverseReadPairs();
         } else if (walker instanceof ActiveRegionWalker) {
-            switch (engine.getArguments().activeRegionShardType) {
-                case LOCUSSHARD: return new TraverseActiveRegions();
-                case READSHARD: return new ExperimentalReadShardTraverseActiveRegions();
-                case ACTIVEREGIONSHARD: return new ExperimentalActiveRegionShardTraverseActiveRegions();
-                default: throw new UnsupportedOperationException("Unable to determine traversal type, the walker is an unknown type of ActiveRegionWalker.");
-            }
+            return new TraverseActiveRegions();
         } else {
             throw new UnsupportedOperationException("Unable to determine traversal type, the walker is an unknown type.");
         }
diff --git a/public/java/src/org/broadinstitute/sting/gatk/traversals/ExperimentalActiveRegionShardTraverseActiveRegions.java b/public/java/src/org/broadinstitute/sting/gatk/traversals/ExperimentalActiveRegionShardTraverseActiveRegions.java
deleted file mode 100644
index 45d132678..000000000
--- a/public/java/src/org/broadinstitute/sting/gatk/traversals/ExperimentalActiveRegionShardTraverseActiveRegions.java
+++ /dev/null
@@ -1,309 +0,0 @@
-package org.broadinstitute.sting.gatk.traversals;
-
-import net.sf.samtools.SAMFileHeader;
-import org.apache.log4j.Logger;
-import org.broadinstitute.sting.gatk.WalkerManager;
-import org.broadinstitute.sting.gatk.contexts.AlignmentContext;
-import org.broadinstitute.sting.gatk.contexts.ReferenceContext;
-import org.broadinstitute.sting.gatk.datasources.providers.*;
-import org.broadinstitute.sting.gatk.datasources.reads.Shard;
-import org.broadinstitute.sting.gatk.executive.WindowMaker;
-import org.broadinstitute.sting.gatk.refdata.RefMetaDataTracker;
-import org.broadinstitute.sting.gatk.walkers.ActiveRegionExtension;
-import org.broadinstitute.sting.gatk.walkers.ActiveRegionWalker;
-import org.broadinstitute.sting.gatk.walkers.DataSource;
-import org.broadinstitute.sting.gatk.walkers.Walker;
-import org.broadinstitute.sting.utils.GenomeLoc;
-import org.broadinstitute.sting.utils.SampleUtils;
-import org.broadinstitute.sting.utils.activeregion.ActiveRegion;
-import org.broadinstitute.sting.utils.activeregion.ActivityProfile;
-import org.broadinstitute.sting.utils.activeregion.ActivityProfileResult;
-import org.broadinstitute.sting.utils.sam.GATKSAMRecord;
-
-import java.util.*;
-
-public class ExperimentalActiveRegionShardTraverseActiveRegions <M,T> extends TraversalEngine<M,T,ActiveRegionWalker<M,T>,ActiveRegionShardDataProvider> {
-    /**
-     * our log, which we want to capture anything from this class
-     */
-    protected final static Logger logger = Logger.getLogger(TraversalEngine.class);
-
-    private final LinkedList<ActiveRegion> workQueue = new LinkedList<ActiveRegion>();
-    private final LinkedList<GATKSAMRecord> myReads = new LinkedList<GATKSAMRecord>();
-
-    @Override
-    public String getTraversalUnits() {
-        return "active regions";
-    }
-
-    @Override
-    public T traverse( final ActiveRegionWalker<M,T> walker,
-                       final ActiveRegionShardDataProvider dataProvider,
-                       T sum) {
-        logger.debug(String.format("ExperimentalActiveRegionShardTraverseActiveRegions.traverse: Shard is %s", dataProvider));
-
-        ReadShardDataProvider readDataProvider = dataProvider.getReadShardDataProvider();
-
-        final int activeRegionExtension = walker.getClass().getAnnotation(ActiveRegionExtension.class).extension();
-        final int maxRegionSize = walker.getClass().getAnnotation(ActiveRegionExtension.class).maxRegion();
-
-        final ReadView readView = new ReadView(readDataProvider);
-
-        final List<ActiveRegion> activeRegions = new LinkedList<ActiveRegion>();
-        ActivityProfile profile = new ActivityProfile(engine.getGenomeLocParser(), walker.hasPresetActiveRegions());
-
-        Shard readShard = readDataProvider.getShard();
-        SAMFileHeader header = readShard.getReadProperties().getHeader();
-        WindowMaker windowMaker = new WindowMaker(readShard, engine.getGenomeLocParser(),
-                readView.iterator(), readShard.getGenomeLocs(), SampleUtils.getSAMFileSamples(header));
-
-        for(WindowMaker.WindowMakerIterator iterator: windowMaker) {
-            LocusShardDataProvider locusDataProvider = dataProvider.getLocusShardDataProvider(iterator);
-            final LocusView locusView = new AllLocusView(locusDataProvider);
-            final LocusReferenceView referenceView = new LocusReferenceView( walker, locusDataProvider );
-            ReferenceOrderedView referenceOrderedDataView = getReferenceOrderedView(walker, locusDataProvider, locusView);
-
-            // We keep processing while the next reference location is within the interval
-            GenomeLoc prevLoc = null;
-            while( locusView.hasNext() ) {
-                final AlignmentContext locus = locusView.next();
-                final GenomeLoc location = locus.getLocation();
-
-                if ( prevLoc != null && location.getStart() != prevLoc.getStop() + 1 ) {
-                    // we've move across some interval boundary, restart profile
-                    profile = incorporateActiveRegions(profile, activeRegions, activeRegionExtension, maxRegionSize);
-                }
-
-                readDataProvider.getShard().getReadMetrics().incrementNumIterations();
-
-                // create reference context. Note that if we have a pileup of "extended events", the context will
-                // hold the (longest) stretch of deleted reference bases (if deletions are present in the pileup).
-                final ReferenceContext refContext = referenceView.getReferenceContext(location);
-
-                // Iterate forward to get all reference ordered data covering this location
-                final RefMetaDataTracker tracker = referenceOrderedDataView.getReferenceOrderedDataAtLocus(locus.getLocation(), refContext);
-
-                // Call the walkers isActive function for this locus and add them to the list to be integrated later
-                profile.add(walkerActiveProb(walker, tracker, refContext, locus, location));
-
-                prevLoc = location;
-
-                printProgress(locus.getLocation());
-            }
-
-            locusDataProvider.close();
-        }
-
-        windowMaker.close();
-
-        updateCumulativeMetrics(readDataProvider.getShard());
-
-        if ( ! profile.isEmpty() )
-            incorporateActiveRegions(profile, activeRegions, activeRegionExtension, maxRegionSize);
-
-        // add active regions to queue of regions to process
-        // first check if can merge active regions over shard boundaries
-        if( !activeRegions.isEmpty() ) {
-            if( !workQueue.isEmpty() ) {
-                final ActiveRegion last = workQueue.getLast();
-                final ActiveRegion first = activeRegions.get(0);
-                if( last.isActive == first.isActive && last.getLocation().contiguousP(first.getLocation()) && last.getLocation().size() + first.getLocation().size() <= maxRegionSize ) {
-                    workQueue.removeLast();
-                    activeRegions.remove(first);
-                    workQueue.addLast(new ActiveRegion(last.getLocation().union(first.getLocation()), first.isActive, this.engine.getGenomeLocParser(), activeRegionExtension));
-                }
-            }
-            workQueue.addAll( activeRegions );
-        }
-
-        logger.debug("Integrated " + profile.size() + " isActive calls into " + activeRegions.size() + " regions." );
-
-        // now process the active regions, where possible
-        boolean emptyQueue = false;
-        sum = processActiveRegions(walker, sum, emptyQueue);
-
-        return sum;
-    }
-
-    /**
-     * Take the individual isActive calls and integrate them into contiguous active regions and
-     * add these blocks of work to the work queue
-     * band-pass filter the list of isActive probabilities and turn into active regions
-     *
-     * @param profile
-     * @param activeRegions
-     * @param activeRegionExtension
-     * @param maxRegionSize
-     * @return
-     */
-    private ActivityProfile incorporateActiveRegions(final ActivityProfile profile,
-                                                     final List<ActiveRegion> activeRegions,
-                                                     final int activeRegionExtension,
-                                                     final int maxRegionSize) {
-        if ( profile.isEmpty() )
-            throw new IllegalStateException("trying to incorporate an empty active profile " + profile);
-
-        final ActivityProfile bandPassFiltered = profile.bandPassFilter();
-        activeRegions.addAll(bandPassFiltered.createActiveRegions( activeRegionExtension, maxRegionSize ));
-        return new ActivityProfile( engine.getGenomeLocParser(), profile.hasPresetRegions() );
-    }
-
-
-    // --------------------------------------------------------------------------------
-    //
-    // simple utility functions
-    //
-    // --------------------------------------------------------------------------------
-
-    private final ActivityProfileResult walkerActiveProb(final ActiveRegionWalker<M,T> walker,
-                                          final RefMetaDataTracker tracker, final ReferenceContext refContext,
-                                          final AlignmentContext locus, final GenomeLoc location) {
-        if ( walker.hasPresetActiveRegions() ) {
-            return new ActivityProfileResult(location, walker.presetActiveRegions.overlaps(location) ? 1.0 : 0.0);
-        } else {
-            return walker.isActive( tracker, refContext, locus );
-        }
-    }
-
-    private ReferenceOrderedView getReferenceOrderedView( final ActiveRegionWalker<M,T> walker,
-                                                          final LocusShardDataProvider dataProvider,
-                                                          final LocusView locusView) {
-        if ( WalkerManager.getWalkerDataSource(walker) != DataSource.REFERENCE_ORDERED_DATA )
-            return new ManagingReferenceOrderedView( dataProvider );
-        else
-            return (RodLocusView)locusView;
-    }
-
-    // --------------------------------------------------------------------------------
-    //
-    // code to handle processing active regions
-    //
-    // --------------------------------------------------------------------------------
-
-    private T processActiveRegions( final ActiveRegionWalker<M,T> walker, T sum, boolean emptyQueue ) {
-        if( walker.activeRegionOutStream != null ) {
-            writeActiveRegionsToStream(walker);
-            return sum;
-        } else {
-            return callWalkerMapOnActiveRegions(walker, sum, emptyQueue);
-        }
-    }
-
-    /**
-     * Write out each active region to the walker activeRegionOutStream
-     *
-     * @param walker
-     */
-    private void writeActiveRegionsToStream( final ActiveRegionWalker<M,T> walker ) {
-        // Just want to output the active regions to a file, not actually process them
-        for( final ActiveRegion activeRegion : workQueue ) {
-            if( activeRegion.isActive ) {
-                walker.activeRegionOutStream.println( activeRegion.getLocation() );
-            }
-        }
-    }
-
-    private T callWalkerMapOnActiveRegions( final ActiveRegionWalker<M,T> walker, T sum, boolean emptyQueue ) {
-        final int lastRegionStart = workQueue.getLast().getLocation().getStart();
-        final String lastRegionContig = workQueue.getLast().getLocation().getContig();
-
-        // If we've traversed sufficiently past the beginning of the workQueue we can unload those regions and process them
-        // TODO can implement parallel traversal here
-        while( workQueue.peekFirst() != null ) {
-            ActiveRegion firstRegion = workQueue.getFirst();
-            final String firstRegionContig = firstRegion.getLocation().getContig();
-            if (emptyQueue || firstRegionContig != lastRegionContig) {
-                sum = processFirstActiveRegion(sum, walker);
-            }
-            else {
-                final int firstRegionMaxReadStop = walker.wantsExtendedReads() ? firstRegion.getMaxReadStop() : firstRegion.getExtendedMaxReadStop();
-                if (lastRegionStart > firstRegionMaxReadStop) {
-                    sum = processFirstActiveRegion( sum, walker );
-                }
-                else {
-                    break;
-                }
-            }
-        }
-
-        return sum;
-    }
-
-    /**
-     * Process the first active region and all remaining reads which overlap
-     *
-     * Remove the first active region from the queue
-     * (NB: some reads associated with this active region may have already been processed)
-     *
-     * Remove all of these reads from the queue
-     * (NB: some may be associated with other active regions)
-     *
-     * @param sum
-     * @param walker
-     * @return
-     */
-    private T processFirstActiveRegion( final T sum, final ActiveRegionWalker<M,T> walker ) {
-        final ActiveRegion firstRegion = workQueue.removeFirst();
-
-        GATKSAMRecord firstRead = myReads.peekFirst();     // don't remove because it may not be placed here
-        GenomeLoc firstReadLoc = this.engine.getGenomeLocParser().createGenomeLoc( firstRead );
-
-        while ( firstRegion.getLocation().overlapsP( firstReadLoc ) ||
-                (walker.wantsExtendedReads() && firstRegion.getExtendedLoc().overlapsP( firstReadLoc ))) {
-            if( firstRegion.getLocation().overlapsP( firstReadLoc ) ) {
-                // The region which the highest amount of overlap is chosen as the primary region for the read (tie breaking is done as right most region)
-                long maxOverlap = firstRegion.getLocation().sizeOfOverlap( firstReadLoc );
-                ActiveRegion bestRegion = firstRegion;
-                for( final ActiveRegion otherRegionToTest : workQueue ) {
-                    if( otherRegionToTest.getLocation().sizeOfOverlap(firstReadLoc) >= maxOverlap ) {
-                        maxOverlap = otherRegionToTest.getLocation().sizeOfOverlap( firstReadLoc );
-                        bestRegion = otherRegionToTest;
-                    }
-                }
-                bestRegion.add( firstRead );
-
-                // The read is also added to all other regions in which it overlaps but marked as non-primary
-                if( walker.wantsNonPrimaryReads() ) {
-                    if( !bestRegion.equals(firstRegion) ) {
-                        firstRegion.add(firstRead);
-                    }
-                    for( final ActiveRegion otherRegionToTest : workQueue ) {
-                        if( !bestRegion.equals(otherRegionToTest) ) {
-                            // check for non-primary vs. extended
-                            if ( otherRegionToTest.getLocation().overlapsP( firstReadLoc ) ) {
-                                otherRegionToTest.add( firstRead );
-                            } else if ( walker.wantsExtendedReads() && otherRegionToTest.getExtendedLoc().overlapsP( firstReadLoc ) ) {
-                                otherRegionToTest.add( firstRead );
-                            }
-                        }
-                    }
-                }
-
-                // check for non-primary vs. extended
-            } else if( firstRegion.getLocation().overlapsP( firstReadLoc ) ) {
-                if ( walker.wantsNonPrimaryReads() ) {
-                    firstRegion.add( firstRead );
-                }
-            } else if( walker.wantsExtendedReads() && firstRegion.getExtendedLoc().overlapsP( firstReadLoc )) {
-                firstRegion.add( firstRead );
-            }
-
-            myReads.removeFirst();
-            firstRead = myReads.peekFirst();
-            firstReadLoc = this.engine.getGenomeLocParser().createGenomeLoc( firstRead );
-        }
-
-        logger.debug(">> Map call with " + firstRegion.getReads().size() + " " + (firstRegion.isActive ? "active" : "inactive") + " reads @ " + firstRegion.getLocation() + " with full extent: " + firstRegion.getReferenceLoc());
-        final M x = walker.map( firstRegion, null );
-        return walker.reduce(x, sum);
-    }
-
-    /**
-     * Special function called in LinearMicroScheduler to empty out the work queue.
-     * Ugly for now but will be cleaned up when we push this functionality more into the engine
-     */
-    public T endTraversal( final Walker<M,T> walker, T sum) {
-        boolean emptyQueue = true;
-        return processActiveRegions((ActiveRegionWalker<M,T>)walker, sum, emptyQueue);
-    }
-}
diff --git a/public/java/src/org/broadinstitute/sting/gatk/traversals/ExperimentalReadShardTraverseActiveRegions.java b/public/java/src/org/broadinstitute/sting/gatk/traversals/ExperimentalReadShardTraverseActiveRegions.java
deleted file mode 100644
index 299ee4f56..000000000
--- a/public/java/src/org/broadinstitute/sting/gatk/traversals/ExperimentalReadShardTraverseActiveRegions.java
+++ /dev/null
@@ -1,309 +0,0 @@
-package org.broadinstitute.sting.gatk.traversals;
-
-import net.sf.samtools.SAMFileHeader;
-import org.apache.log4j.Logger;
-import org.broadinstitute.sting.gatk.WalkerManager;
-import org.broadinstitute.sting.gatk.contexts.AlignmentContext;
-import org.broadinstitute.sting.gatk.contexts.ReferenceContext;
-import org.broadinstitute.sting.gatk.datasources.providers.*;
-import org.broadinstitute.sting.gatk.datasources.reads.Shard;
-import org.broadinstitute.sting.gatk.executive.WindowMaker;
-import org.broadinstitute.sting.gatk.refdata.RefMetaDataTracker;
-import org.broadinstitute.sting.gatk.walkers.ActiveRegionExtension;
-import org.broadinstitute.sting.gatk.walkers.ActiveRegionWalker;
-import org.broadinstitute.sting.gatk.walkers.DataSource;
-import org.broadinstitute.sting.gatk.walkers.Walker;
-import org.broadinstitute.sting.utils.GenomeLoc;
-import org.broadinstitute.sting.utils.SampleUtils;
-import org.broadinstitute.sting.utils.activeregion.ActiveRegion;
-import org.broadinstitute.sting.utils.activeregion.ActivityProfile;
-import org.broadinstitute.sting.utils.activeregion.ActivityProfileResult;
-import org.broadinstitute.sting.utils.sam.GATKSAMRecord;
-
-import java.util.*;
-
-public class ExperimentalReadShardTraverseActiveRegions <M,T> extends TraversalEngine<M,T,ActiveRegionWalker<M,T>,ReadShardDataProvider> {
-    /**
-     * our log, which we want to capture anything from this class
-     */
-    protected final static Logger logger = Logger.getLogger(TraversalEngine.class);
-
-    private final LinkedList<ActiveRegion> workQueue = new LinkedList<ActiveRegion>();
-    private final LinkedList<GATKSAMRecord> myReads = new LinkedList<GATKSAMRecord>();
-
-    @Override
-    public String getTraversalUnits() {
-        return "active regions";
-    }
-
-    @Override
-    public T traverse( final ActiveRegionWalker<M,T> walker,
-                       final ReadShardDataProvider readDataProvider,
-                       T sum) {
-        logger.debug(String.format("ExperimentalReadShardTraverseActiveRegions.traverse: Read Shard is %s", readDataProvider));
-
-        final int activeRegionExtension = walker.getClass().getAnnotation(ActiveRegionExtension.class).extension();
-        final int maxRegionSize = walker.getClass().getAnnotation(ActiveRegionExtension.class).maxRegion();
-
-        final ReadView readView = new ReadView(readDataProvider);
-
-        final List<ActiveRegion> activeRegions = new LinkedList<ActiveRegion>();
-        ActivityProfile profile = new ActivityProfile(engine.getGenomeLocParser(), walker.hasPresetActiveRegions());
-
-        Shard readShard = readDataProvider.getShard();
-        SAMFileHeader header = readShard.getReadProperties().getHeader();
-        WindowMaker windowMaker = new WindowMaker(readShard, engine.getGenomeLocParser(),
-                readView.iterator(), readShard.getGenomeLocs(), SampleUtils.getSAMFileSamples(header));
-
-        for(WindowMaker.WindowMakerIterator iterator: windowMaker) {
-            LocusShardDataProvider locusDataProvider = new LocusShardDataProvider(readDataProvider,
-                    iterator.getSourceInfo(), engine.getGenomeLocParser(), iterator.getLocus(), iterator);
-
-            final LocusView locusView = new AllLocusView(locusDataProvider);
-            final LocusReferenceView referenceView = new LocusReferenceView( walker, locusDataProvider );
-            ReferenceOrderedView referenceOrderedDataView = getReferenceOrderedView(walker, locusDataProvider, locusView);
-
-            // We keep processing while the next reference location is within the interval
-            GenomeLoc prevLoc = null;
-            while( locusView.hasNext() ) {
-                final AlignmentContext locus = locusView.next();
-                final GenomeLoc location = locus.getLocation();
-
-                if ( prevLoc != null && location.getStart() != prevLoc.getStop() + 1 ) {
-                    // we've move across some interval boundary, restart profile
-                    profile = incorporateActiveRegions(profile, activeRegions, activeRegionExtension, maxRegionSize);
-                }
-
-                readDataProvider.getShard().getReadMetrics().incrementNumIterations();
-
-                // create reference context. Note that if we have a pileup of "extended events", the context will
-                // hold the (longest) stretch of deleted reference bases (if deletions are present in the pileup).
-                final ReferenceContext refContext = referenceView.getReferenceContext(location);
-
-                // Iterate forward to get all reference ordered data covering this location
-                final RefMetaDataTracker tracker = referenceOrderedDataView.getReferenceOrderedDataAtLocus(locus.getLocation(), refContext);
-
-                // Call the walkers isActive function for this locus and add them to the list to be integrated later
-                profile.add(walkerActiveProb(walker, tracker, refContext, locus, location));
-
-                prevLoc = location;
-
-                printProgress(locus.getLocation());
-            }
-
-            locusDataProvider.close();
-        }
-
-        windowMaker.close();
-
-        updateCumulativeMetrics(readDataProvider.getShard());
-
-        if ( ! profile.isEmpty() )
-            incorporateActiveRegions(profile, activeRegions, activeRegionExtension, maxRegionSize);
-
-        // add active regions to queue of regions to process
-        // first check if can merge active regions over shard boundaries
-        if( !activeRegions.isEmpty() ) {
-            if( !workQueue.isEmpty() ) {
-                final ActiveRegion last = workQueue.getLast();
-                final ActiveRegion first = activeRegions.get(0);
-                if( last.isActive == first.isActive && last.getLocation().contiguousP(first.getLocation()) && last.getLocation().size() + first.getLocation().size() <= maxRegionSize ) {
-                    workQueue.removeLast();
-                    activeRegions.remove(first);
-                    workQueue.addLast(new ActiveRegion(last.getLocation().union(first.getLocation()), first.isActive, this.engine.getGenomeLocParser(), activeRegionExtension));
-                }
-            }
-            workQueue.addAll( activeRegions );
-        }
-
-        logger.debug("Integrated " + profile.size() + " isActive calls into " + activeRegions.size() + " regions." );
-
-        // now process the active regions, where possible
-        boolean emptyQueue = false;
-        sum = processActiveRegions(walker, sum, emptyQueue);
-
-        return sum;
-    }
-
-    /**
-     * Take the individual isActive calls and integrate them into contiguous active regions and
-     * add these blocks of work to the work queue
-     * band-pass filter the list of isActive probabilities and turn into active regions
-     *
-     * @param profile
-     * @param activeRegions
-     * @param activeRegionExtension
-     * @param maxRegionSize
-     * @return
-     */
-    private ActivityProfile incorporateActiveRegions(final ActivityProfile profile,
-                                                     final List<ActiveRegion> activeRegions,
-                                                     final int activeRegionExtension,
-                                                     final int maxRegionSize) {
-        if ( profile.isEmpty() )
-            throw new IllegalStateException("trying to incorporate an empty active profile " + profile);
-
-        final ActivityProfile bandPassFiltered = profile.bandPassFilter();
-        activeRegions.addAll(bandPassFiltered.createActiveRegions( activeRegionExtension, maxRegionSize ));
-        return new ActivityProfile( engine.getGenomeLocParser(), profile.hasPresetRegions() );
-    }
-
-
-    // --------------------------------------------------------------------------------
-    //
-    // simple utility functions
-    //
-    // --------------------------------------------------------------------------------
-
-    private final ActivityProfileResult walkerActiveProb(final ActiveRegionWalker<M,T> walker,
-                                          final RefMetaDataTracker tracker, final ReferenceContext refContext,
-                                          final AlignmentContext locus, final GenomeLoc location) {
-        if ( walker.hasPresetActiveRegions() ) {
-            return new ActivityProfileResult(location, walker.presetActiveRegions.overlaps(location) ? 1.0 : 0.0);
-        } else {
-            return walker.isActive( tracker, refContext, locus );
-        }
-    }
-
-    private ReferenceOrderedView getReferenceOrderedView( final ActiveRegionWalker<M,T> walker,
-                                                          final LocusShardDataProvider dataProvider,
-                                                          final LocusView locusView) {
-        if ( WalkerManager.getWalkerDataSource(walker) != DataSource.REFERENCE_ORDERED_DATA )
-            return new ManagingReferenceOrderedView( dataProvider );
-        else
-            return (RodLocusView)locusView;
-    }
-
-    // --------------------------------------------------------------------------------
-    //
-    // code to handle processing active regions
-    //
-    // --------------------------------------------------------------------------------
-
-    private T processActiveRegions( final ActiveRegionWalker<M,T> walker, T sum, boolean emptyQueue ) {
-        if( walker.activeRegionOutStream != null ) {
-            writeActiveRegionsToStream(walker);
-            return sum;
-        } else {
-            return callWalkerMapOnActiveRegions(walker, sum, emptyQueue);
-        }
-    }
-
-    /**
-     * Write out each active region to the walker activeRegionOutStream
-     *
-     * @param walker
-     */
-    private void writeActiveRegionsToStream( final ActiveRegionWalker<M,T> walker ) {
-        // Just want to output the active regions to a file, not actually process them
-        for( final ActiveRegion activeRegion : workQueue ) {
-            if( activeRegion.isActive ) {
-                walker.activeRegionOutStream.println( activeRegion.getLocation() );
-            }
-        }
-    }
-
-    private T callWalkerMapOnActiveRegions( final ActiveRegionWalker<M,T> walker, T sum, boolean emptyQueue ) {
-        final int lastRegionStart = workQueue.getLast().getLocation().getStart();
-        final String lastRegionContig = workQueue.getLast().getLocation().getContig();
-
-        // If we've traversed sufficiently past the beginning of the workQueue we can unload those regions and process them
-        // TODO can implement parallel traversal here
-        while( workQueue.peekFirst() != null ) {
-            ActiveRegion firstRegion = workQueue.getFirst();
-            final String firstRegionContig = firstRegion.getLocation().getContig();
-            if (emptyQueue || firstRegionContig != lastRegionContig) {
-                sum = processFirstActiveRegion(sum, walker);
-            }
-            else {
-                final int firstRegionMaxReadStop = walker.wantsExtendedReads() ? firstRegion.getMaxReadStop() : firstRegion.getExtendedMaxReadStop();
-                if (lastRegionStart > firstRegionMaxReadStop) {
-                    sum = processFirstActiveRegion( sum, walker );
-                }
-                else {
-                    break;
-                }
-            }
-        }
-
-        return sum;
-    }
-
-    /**
-     * Process the first active region and all remaining reads which overlap
-     *
-     * Remove the first active region from the queue
-     * (NB: some reads associated with this active region may have already been processed)
-     *
-     * Remove all of these reads from the queue
-     * (NB: some may be associated with other active regions)
-     *
-     * @param sum
-     * @param walker
-     * @return
-     */
-    private T processFirstActiveRegion( final T sum, final ActiveRegionWalker<M,T> walker ) {
-        final ActiveRegion firstRegion = workQueue.removeFirst();
-
-        GATKSAMRecord firstRead = myReads.peekFirst();     // don't remove because it may not be placed here
-        GenomeLoc firstReadLoc = this.engine.getGenomeLocParser().createGenomeLoc( firstRead );
-
-        while ( firstRegion.getLocation().overlapsP( firstReadLoc ) ||
-                (walker.wantsExtendedReads() && firstRegion.getExtendedLoc().overlapsP( firstReadLoc ))) {
-            if( firstRegion.getLocation().overlapsP( firstReadLoc ) ) {
-                // The region which the highest amount of overlap is chosen as the primary region for the read (tie breaking is done as right most region)
-                long maxOverlap = firstRegion.getLocation().sizeOfOverlap( firstReadLoc );
-                ActiveRegion bestRegion = firstRegion;
-                for( final ActiveRegion otherRegionToTest : workQueue ) {
-                    if( otherRegionToTest.getLocation().sizeOfOverlap(firstReadLoc) >= maxOverlap ) {
-                        maxOverlap = otherRegionToTest.getLocation().sizeOfOverlap( firstReadLoc );
-                        bestRegion = otherRegionToTest;
-                    }
-                }
-                bestRegion.add( firstRead );
-
-                // The read is also added to all other regions in which it overlaps but marked as non-primary
-                if( walker.wantsNonPrimaryReads() ) {
-                    if( !bestRegion.equals(firstRegion) ) {
-                        firstRegion.add(firstRead);
-                    }
-                    for( final ActiveRegion otherRegionToTest : workQueue ) {
-                        if( !bestRegion.equals(otherRegionToTest) ) {
-                            // check for non-primary vs. extended
-                            if ( otherRegionToTest.getLocation().overlapsP( firstReadLoc ) ) {
-                                otherRegionToTest.add( firstRead );
-                            } else if ( walker.wantsExtendedReads() && otherRegionToTest.getExtendedLoc().overlapsP( firstReadLoc ) ) {
-                                otherRegionToTest.add( firstRead );
-                            }
-                        }
-                    }
-                }
-
-                // check for non-primary vs. extended
-            } else if( firstRegion.getLocation().overlapsP( firstReadLoc ) ) {
-                if ( walker.wantsNonPrimaryReads() ) {
-                    firstRegion.add( firstRead );
-                }
-            } else if( walker.wantsExtendedReads() && firstRegion.getExtendedLoc().overlapsP( firstReadLoc )) {
-                firstRegion.add( firstRead );
-            }
-
-            myReads.removeFirst();
-            firstRead = myReads.peekFirst();
-            firstReadLoc = this.engine.getGenomeLocParser().createGenomeLoc( firstRead );
-        }
-
-        logger.debug(">> Map call with " + firstRegion.getReads().size() + " " + (firstRegion.isActive ? "active" : "inactive") + " reads @ " + firstRegion.getLocation() + " with full extent: " + firstRegion.getReferenceLoc());
-        final M x = walker.map( firstRegion, null );
-        return walker.reduce(x, sum);
-    }
-
-    /**
-     * Special function called in LinearMicroScheduler to empty out the work queue.
-     * Ugly for now but will be cleaned up when we push this functionality more into the engine
-     */
-    public T endTraversal( final Walker<M,T> walker, T sum) {
-        boolean emptyQueue = true;
-        return processActiveRegions((ActiveRegionWalker<M,T>)walker, sum, emptyQueue);
-    }
-}
diff --git a/public/java/src/org/broadinstitute/sting/gatk/traversals/TraverseDuplicates.java b/public/java/src/org/broadinstitute/sting/gatk/traversals/TraverseDuplicates.java
index 2e43ef8f8..8ebea8b54 100755
--- a/public/java/src/org/broadinstitute/sting/gatk/traversals/TraverseDuplicates.java
+++ b/public/java/src/org/broadinstitute/sting/gatk/traversals/TraverseDuplicates.java
@@ -197,7 +197,7 @@ public class TraverseDuplicates<M,T> extends TraversalEngine<M,T,DuplicateWalker
             }
 
             updateCumulativeMetrics(dataProvider.getShard());
-            printProgress(site);
+            printProgress(site.getStopLocation());
             done = walker.isDone();
         }
 
diff --git a/public/java/src/org/broadinstitute/sting/gatk/walkers/annotator/AverageAltAlleleLength.java b/public/java/src/org/broadinstitute/sting/gatk/walkers/annotator/AverageAltAlleleLength.java
new file mode 100644
index 000000000..d6768cb37
--- /dev/null
+++ b/public/java/src/org/broadinstitute/sting/gatk/walkers/annotator/AverageAltAlleleLength.java
@@ -0,0 +1,92 @@
+package org.broadinstitute.sting.gatk.walkers.annotator;
+
+import org.broadinstitute.sting.gatk.contexts.AlignmentContext;
+import org.broadinstitute.sting.gatk.contexts.ReferenceContext;
+import org.broadinstitute.sting.gatk.refdata.RefMetaDataTracker;
+import org.broadinstitute.sting.gatk.walkers.annotator.interfaces.ActiveRegionBasedAnnotation;
+import org.broadinstitute.sting.gatk.walkers.annotator.interfaces.AnnotatorCompatible;
+import org.broadinstitute.sting.gatk.walkers.annotator.interfaces.ExperimentalAnnotation;
+import org.broadinstitute.sting.gatk.walkers.annotator.interfaces.InfoFieldAnnotation;
+import org.broadinstitute.sting.utils.genotyper.PerReadAlleleLikelihoodMap;
+import org.broadinstitute.variant.variantcontext.Allele;
+import org.broadinstitute.variant.variantcontext.Genotype;
+import org.broadinstitute.variant.variantcontext.GenotypesContext;
+import org.broadinstitute.variant.variantcontext.VariantContext;
+import org.broadinstitute.variant.vcf.VCFHeaderLineType;
+import org.broadinstitute.variant.vcf.VCFInfoHeaderLine;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Created by IntelliJ IDEA.
+ * User: chartl
+ * Date: 1/3/13
+ * Time: 11:36 AM
+ * To change this template use File | Settings | File Templates.
+ */
+public class AverageAltAlleleLength extends InfoFieldAnnotation implements ActiveRegionBasedAnnotation, ExperimentalAnnotation {
+
+    public List<VCFInfoHeaderLine> getDescriptions() {
+        return Arrays.asList(new VCFInfoHeaderLine(getKeyNames().get(0), 1, VCFHeaderLineType.Float, "Average Allele Length"));
+    }
+
+    public List<String> getKeyNames() { return Arrays.asList("AAL"); }
+
+    public Map<String, Object> annotate(final RefMetaDataTracker tracker,
+                                        final AnnotatorCompatible walker,
+                                        final ReferenceContext ref,
+                                        final Map<String, AlignmentContext> stratifiedContexts,
+                                        final VariantContext vc,
+                                        final Map<String, PerReadAlleleLikelihoodMap> perReadAlleleLikelihoodMap ) {
+        if ( !vc.hasLog10PError() )
+            return null;
+
+        final GenotypesContext genotypes = vc.getGenotypes();
+        if ( genotypes == null || genotypes.size() == 0 )
+            return null;
+
+        Map<String, Object> map = new HashMap<String, Object>();
+
+        double length = getMeanAltAlleleLength(vc);
+        map.put(getKeyNames().get(0),String.format("%.2f",length));
+        return map;
+    }
+
+    public static double getMeanAltAlleleLength(VariantContext vc) {
+        double averageLength = 1.0;
+        if ( ! vc.isSNP() && ! vc.isSymbolic() ) {
+            // adjust for the event length
+            int averageLengthNum = 0;
+            int averageLengthDenom = 0;
+            int refLength = vc.getReference().length();
+            for ( Allele a : vc.getAlternateAlleles() ) {
+                int numAllele = vc.getCalledChrCount(a);
+                int alleleSize;
+                if ( a.length() == refLength ) {
+                    // SNP or MNP
+                    byte[] a_bases = a.getBases();
+                    byte[] ref_bases = vc.getReference().getBases();
+                    int n_mismatch = 0;
+                    for ( int idx = 0; idx < a_bases.length; idx++ ) {
+                        if ( a_bases[idx] != ref_bases[idx] )
+                            n_mismatch++;
+                    }
+                    alleleSize = n_mismatch;
+                }
+                else if ( a.isSymbolic() ) {
+                    alleleSize = 1;
+                } else {
+                    alleleSize = Math.abs(refLength-a.length());
+                }
+                averageLengthNum += alleleSize*numAllele;
+                averageLengthDenom += numAllele;
+            }
+            averageLength = ( (double) averageLengthNum )/averageLengthDenom;
+        }
+
+        return averageLength;
+    }
+}
diff --git a/public/java/src/org/broadinstitute/sting/gatk/walkers/annotator/QualByDepth.java b/public/java/src/org/broadinstitute/sting/gatk/walkers/annotator/QualByDepth.java
index 24bac9deb..253313f8f 100755
--- a/public/java/src/org/broadinstitute/sting/gatk/walkers/annotator/QualByDepth.java
+++ b/public/java/src/org/broadinstitute/sting/gatk/walkers/annotator/QualByDepth.java
@@ -1,5 +1,6 @@
 package org.broadinstitute.sting.gatk.walkers.annotator;
 
+import com.sun.org.apache.bcel.internal.generic.AALOAD;
 import org.broadinstitute.sting.gatk.contexts.AlignmentContext;
 import org.broadinstitute.sting.gatk.contexts.ReferenceContext;
 import org.broadinstitute.sting.gatk.refdata.RefMetaDataTracker;
@@ -68,50 +69,17 @@ public class QualByDepth extends InfoFieldAnnotation implements StandardAnnotati
         if ( depth == 0 )
             return null;
 
-        double QD = -10.0 * vc.getLog10PError() / (double)depth;
+        double altAlleleLength = AverageAltAlleleLength.getMeanAltAlleleLength(vc);
+        double QD = -10.0 * vc.getLog10PError() / ((double)depth * altAlleleLength);
         Map<String, Object> map = new HashMap<String, Object>();
-
-        if ( ! vc.isSNP() && ! vc.isSymbolic() ) {
-            // adjust for the event length
-            int averageLengthNum = 0;
-            int averageLengthDenom = 0;
-            int refLength = vc.getReference().length();
-            for ( Allele a : vc.getAlternateAlleles() ) {
-                int numAllele = vc.getCalledChrCount(a);
-                int alleleSize;
-                if ( a.length() == refLength ) {
-                    // SNP or MNP
-                    byte[] a_bases = a.getBases();
-                    byte[] ref_bases = vc.getReference().getBases();
-                    int n_mismatch = 0;
-                    for ( int idx = 0; idx < a_bases.length; idx++ ) {
-                        if ( a_bases[idx] != ref_bases[idx] )
-                            n_mismatch++;
-                    }
-                    alleleSize = n_mismatch;
-                }
-                else if ( a.isSymbolic() ) {
-                    alleleSize = 1;
-                } else {
-                    alleleSize = Math.abs(refLength-a.length());
-                }
-                averageLengthNum += alleleSize*numAllele;
-                averageLengthDenom += numAllele;
-            }
-            double averageLength = ( (double) averageLengthNum )/averageLengthDenom;
-            QD /= averageLength;
-            map.put(getKeyNames().get(1),String.format("%.2f",averageLength));
-        }
-
         map.put(getKeyNames().get(0), String.format("%.2f", QD));
         return map;
     }
 
-    public List<String> getKeyNames() { return Arrays.asList("QD","AAL"); }
+    public List<String> getKeyNames() { return Arrays.asList("QD"); }
 
     public List<VCFInfoHeaderLine> getDescriptions() {
-        return Arrays.asList(new VCFInfoHeaderLine(getKeyNames().get(0), 1, VCFHeaderLineType.Float, "Variant Confidence/Quality by Depth"),
-                             new VCFInfoHeaderLine(getKeyNames().get(1), 1, VCFHeaderLineType.Float, "Average Allele Length"));
+        return Arrays.asList(new VCFInfoHeaderLine(getKeyNames().get(0), 1, VCFHeaderLineType.Float, "Variant Confidence/Quality by Depth"));
     }
 
 
diff --git a/public/java/src/org/broadinstitute/sting/gatk/walkers/bqsr/RecalibrationEngine.java b/public/java/src/org/broadinstitute/sting/gatk/walkers/bqsr/RecalibrationEngine.java
index 95ccecd6e..ca9fb4bca 100644
--- a/public/java/src/org/broadinstitute/sting/gatk/walkers/bqsr/RecalibrationEngine.java
+++ b/public/java/src/org/broadinstitute/sting/gatk/walkers/bqsr/RecalibrationEngine.java
@@ -27,10 +27,7 @@ package org.broadinstitute.sting.gatk.walkers.bqsr;
 
 import com.google.java.contract.Requires;
 import org.broadinstitute.sting.utils.collections.NestedIntegerArray;
-import org.broadinstitute.sting.utils.recalibration.EventType;
-import org.broadinstitute.sting.utils.recalibration.ReadCovariates;
-import org.broadinstitute.sting.utils.recalibration.RecalDatum;
-import org.broadinstitute.sting.utils.recalibration.RecalibrationTables;
+import org.broadinstitute.sting.utils.recalibration.*;
 import org.broadinstitute.sting.utils.recalibration.covariates.Covariate;
 import org.broadinstitute.sting.utils.sam.GATKSAMRecord;
 
@@ -128,29 +125,19 @@ public class RecalibrationEngine {
                     final byte qual = recalInfo.getQual(eventType, offset);
                     final double isError = recalInfo.getErrorFraction(eventType, offset);
 
-                    incrementDatumOrPutIfNecessary(qualityScoreTable, qual, isError, keys[0], keys[1], eventIndex);
+                    RecalUtils.incrementDatumOrPutIfNecessary(qualityScoreTable, qual, isError, keys[0], keys[1], eventIndex);
 
                     for (int i = 2; i < covariates.length; i++) {
                         if (keys[i] < 0)
                             continue;
 
-                        incrementDatumOrPutIfNecessary(tables.getTable(i), qual, isError, keys[0], keys[1], keys[i], eventIndex);
+                        RecalUtils.incrementDatumOrPutIfNecessary(tables.getTable(i), qual, isError, keys[0], keys[1], keys[i], eventIndex);
                     }
                 }
             }
         }
     }
 
-    /**
-     * creates a datum object with one observation and one or zero error
-     *
-     * @param reportedQual  the quality score reported by the instrument for this base
-     * @param isError       whether or not the observation is an error
-     * @return a new RecalDatum object with the observation and the error
-     */
-    protected RecalDatum createDatumObject(final byte reportedQual, final double isError) {
-        return new RecalDatum(1, isError, reportedQual);
-    }
 
     /**
      * Finalize, if appropriate, all derived data in recalibrationTables.
@@ -226,36 +213,4 @@ public class RecalibrationEngine {
         if ( ! finalized ) throw new IllegalStateException("Cannot get final recalibration tables until finalizeData() has been called");
         return finalRecalibrationTables;
     }
-
-    /**
-     * Increments the RecalDatum at the specified position in the specified table, or put a new item there
-     * if there isn't already one.
-     *
-     * Does this in a thread-safe way WITHOUT being synchronized: relies on the behavior of NestedIntegerArray.put()
-     * to return false if another thread inserts a new item at our position in the middle of our put operation.
-     *
-     * @param table the table that holds/will hold our item
-     * @param qual qual for this event
-     * @param isError error value for this event
-     * @param keys location in table of our item
-     */
-    protected void incrementDatumOrPutIfNecessary( final NestedIntegerArray<RecalDatum> table,
-                                                   final byte qual,
-                                                   final double isError,
-                                                   final int... keys ) {
-        final RecalDatum existingDatum = table.get(keys);
-
-        if ( existingDatum == null ) {
-            // No existing item, try to put a new one
-            if ( ! table.put(createDatumObject(qual, isError), keys) ) {
-                // Failed to put a new item because another thread came along and put an item here first.
-                // Get the newly-put item and increment it (item is guaranteed to exist at this point)
-                table.get(keys).increment(1L, isError);
-            }
-        }
-        else {
-            // Easy case: already an item here, so increment it
-            existingDatum.increment(1L, isError);
-        }
-    }
 }
diff --git a/public/java/src/org/broadinstitute/sting/utils/activeregion/ActiveRegion.java b/public/java/src/org/broadinstitute/sting/utils/activeregion/ActiveRegion.java
index d1199ad3d..c12dfcee9 100644
--- a/public/java/src/org/broadinstitute/sting/utils/activeregion/ActiveRegion.java
+++ b/public/java/src/org/broadinstitute/sting/utils/activeregion/ActiveRegion.java
@@ -26,11 +26,6 @@ public class ActiveRegion implements HasGenomeLocation {
     private final GenomeLocParser genomeLocParser;
     public final boolean isActive;
 
-    // maximum stop position of all reads with start position in this active region
-    // Used only by ExperimentalReadShardTraverseActiveRegions
-    // NB: these reads may not be associated with this active region!
-    private int maxReadStop;
-
     public ActiveRegion( final GenomeLoc activeRegionLoc, final boolean isActive, final GenomeLocParser genomeLocParser, final int extension ) {
         this.activeRegionLoc = activeRegionLoc;
         this.isActive = isActive;
@@ -38,7 +33,6 @@ public class ActiveRegion implements HasGenomeLocation {
         this.extension = extension;
         extendedLoc = genomeLocParser.createGenomeLocOnContig(activeRegionLoc.getContig(), activeRegionLoc.getStart() - extension, activeRegionLoc.getStop() + extension);
         fullExtentReferenceLoc = extendedLoc;
-        maxReadStop = activeRegionLoc.getStart();
     }
 
     @Override
@@ -99,18 +93,6 @@ public class ActiveRegion implements HasGenomeLocation {
     public void remove( final GATKSAMRecord read ) { reads.remove( read ); }
     public void removeAll( final ArrayList<GATKSAMRecord> readsToRemove ) { reads.removeAll( readsToRemove ); }
 
-    public void setMaxReadStop(int maxReadStop) {
-        this.maxReadStop = maxReadStop;
-    }
-
-    public int getMaxReadStop() {
-        return maxReadStop;
-    }
-
-    public int getExtendedMaxReadStop() {
-        return maxReadStop + extension;
-    }
-
     public boolean equalExceptReads(final ActiveRegion other) {
         if ( activeRegionLoc.compareTo(other.activeRegionLoc) != 0 ) return false;
         if ( isActive != other.isActive ) return false;
diff --git a/public/java/src/org/broadinstitute/sting/utils/activeregion/ExperimentalActiveRegionShardType.java b/public/java/src/org/broadinstitute/sting/utils/activeregion/ExperimentalActiveRegionShardType.java
deleted file mode 100644
index 1e9a0ee94..000000000
--- a/public/java/src/org/broadinstitute/sting/utils/activeregion/ExperimentalActiveRegionShardType.java
+++ /dev/null
@@ -1,14 +0,0 @@
-package org.broadinstitute.sting.utils.activeregion;
-
-/**
- * Created with IntelliJ IDEA.
- * User: thibault
- * Date: 1/2/13
- * Time: 4:59 PM
- * To change this template use File | Settings | File Templates.
- */
-public enum ExperimentalActiveRegionShardType {
-    LOCUSSHARD,         // default/legacy type
-    READSHARD,
-    ACTIVEREGIONSHARD
-}
diff --git a/public/java/src/org/broadinstitute/sting/utils/recalibration/RecalUtils.java b/public/java/src/org/broadinstitute/sting/utils/recalibration/RecalUtils.java
index cf27df2eb..196f9a115 100644
--- a/public/java/src/org/broadinstitute/sting/utils/recalibration/RecalUtils.java
+++ b/public/java/src/org/broadinstitute/sting/utils/recalibration/RecalUtils.java
@@ -269,9 +269,9 @@ public class RecalUtils {
 
             final ArrayList<Pair<String, String>> columnNames = new ArrayList<Pair<String, String>>(); // initialize the array to hold the column names
             columnNames.add(new Pair<String, String>(covariateNameMap.get(requestedCovariates[0]), "%s")); // save the required covariate name so we can reference it in the future
-            if (tableIndex != RecalibrationTables.TableType.READ_GROUP_TABLE.index) {
+            if (tableIndex != RecalibrationTables.TableType.READ_GROUP_TABLE.ordinal()) {
                 columnNames.add(new Pair<String, String>(covariateNameMap.get(requestedCovariates[1]), "%s")); // save the required covariate name so we can reference it in the future
-                if (tableIndex >= RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.index) {
+                if (tableIndex >= RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.ordinal()) {
                     columnNames.add(covariateValue);
                     columnNames.add(covariateName);
                 }
@@ -279,13 +279,13 @@ public class RecalUtils {
 
             columnNames.add(eventType); // the order of these column names is important here
             columnNames.add(empiricalQuality);
-            if (tableIndex == RecalibrationTables.TableType.READ_GROUP_TABLE.index)
+            if (tableIndex == RecalibrationTables.TableType.READ_GROUP_TABLE.ordinal())
                 columnNames.add(estimatedQReported); // only the read group table needs the estimated Q reported
             columnNames.add(nObservations);
             columnNames.add(nErrors);
 
             final GATKReportTable reportTable;
-            if (tableIndex <= RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.index) {
+            if (tableIndex <= RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.ordinal()) {
                 if(sortByCols) {
                     reportTable = new GATKReportTable("RecalTable" + reportTableIndex++, "", columnNames.size(), GATKReportTable.TableSortingWay.SORT_BY_COLUMN);
                 } else {
@@ -295,7 +295,7 @@ public class RecalUtils {
                     reportTable.addColumn(columnName.getFirst(), columnName.getSecond());
                 rowIndex = 0; // reset the row index since we're starting with a new table
             } else {
-                reportTable = result.get(RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.index);
+                reportTable = result.get(RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.ordinal());
             }
 
             final NestedIntegerArray<RecalDatum> table = recalibrationTables.getTable(tableIndex);
@@ -306,9 +306,9 @@ public class RecalUtils {
                 int columnIndex = 0;
                 int keyIndex = 0;
                 reportTable.set(rowIndex, columnNames.get(columnIndex++).getFirst(), requestedCovariates[0].formatKey(keys[keyIndex++]));
-                if (tableIndex != RecalibrationTables.TableType.READ_GROUP_TABLE.index) {
+                if (tableIndex != RecalibrationTables.TableType.READ_GROUP_TABLE.ordinal()) {
                     reportTable.set(rowIndex, columnNames.get(columnIndex++).getFirst(), requestedCovariates[1].formatKey(keys[keyIndex++]));
-                    if (tableIndex >= RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.index) {
+                    if (tableIndex >= RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.ordinal()) {
                         final Covariate covariate = requestedCovariates[tableIndex];
 
                         reportTable.set(rowIndex, columnNames.get(columnIndex++).getFirst(), covariate.formatKey(keys[keyIndex++]));
@@ -320,7 +320,7 @@ public class RecalUtils {
                 reportTable.set(rowIndex, columnNames.get(columnIndex++).getFirst(), event.toString());
 
                 reportTable.set(rowIndex, columnNames.get(columnIndex++).getFirst(), datum.getEmpiricalQuality());
-                if (tableIndex == RecalibrationTables.TableType.READ_GROUP_TABLE.index)
+                if (tableIndex == RecalibrationTables.TableType.READ_GROUP_TABLE.ordinal())
                     reportTable.set(rowIndex, columnNames.get(columnIndex++).getFirst(), datum.getEstimatedQReported()); // we only add the estimated Q reported in the RG table
                 reportTable.set(rowIndex, columnNames.get(columnIndex++).getFirst(), datum.getNumObservations());
                 reportTable.set(rowIndex, columnNames.get(columnIndex).getFirst(), datum.getNumMismatches());
@@ -414,7 +414,7 @@ public class RecalUtils {
         }
 
         // add the optional covariates to the delta table
-        for (int i = RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.index; i < requestedCovariates.length; i++) {
+        for (int i = RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.ordinal(); i < requestedCovariates.length; i++) {
             final NestedIntegerArray<RecalDatum> covTable = recalibrationTables.getTable(i);
             for (final NestedIntegerArray.Leaf leaf : covTable.getAllLeaves()) {
                 final int[] covs = new int[4];
@@ -458,9 +458,9 @@ public class RecalUtils {
 
     private static List<Object> generateValuesFromKeys(final List<Object> keys, final Covariate[] covariates, final Map<Covariate, String> covariateNameMap) {
         final List<Object> values = new ArrayList<Object>(4);
-        values.add(covariates[RecalibrationTables.TableType.READ_GROUP_TABLE.index].formatKey((Integer)keys.get(0)));
+        values.add(covariates[RecalibrationTables.TableType.READ_GROUP_TABLE.ordinal()].formatKey((Integer)keys.get(0)));
         final int covariateIndex = (Integer)keys.get(1);
-        final Covariate covariate = covariateIndex == covariates.length ? covariates[RecalibrationTables.TableType.QUALITY_SCORE_TABLE.index] : covariates[covariateIndex];
+        final Covariate covariate = covariateIndex == covariates.length ? covariates[RecalibrationTables.TableType.QUALITY_SCORE_TABLE.ordinal()] : covariates[covariateIndex];
         final int covariateKey = (Integer)keys.get(2);
         values.add(covariate.formatKey(covariateKey));
         values.add(covariateNameMap.get(covariate));
@@ -793,4 +793,48 @@ public class RecalUtils {
                 myDatum.combine(row.value);
         }
     }
+
+    /**
+     * Increments the RecalDatum at the specified position in the specified table, or put a new item there
+     * if there isn't already one.
+     *
+     * Does this in a thread-safe way WITHOUT being synchronized: relies on the behavior of NestedIntegerArray.put()
+     * to return false if another thread inserts a new item at our position in the middle of our put operation.
+     *
+     * @param table the table that holds/will hold our item
+     * @param qual qual for this event
+     * @param isError error value for this event
+     * @param keys location in table of our item
+     */
+    public static void incrementDatumOrPutIfNecessary( final NestedIntegerArray<RecalDatum> table,
+                                                          final byte qual,
+                                                          final double isError,
+                                                          final int... keys ) {
+        final RecalDatum existingDatum = table.get(keys);
+
+        if ( existingDatum == null ) {
+            // No existing item, try to put a new one
+            if ( ! table.put(createDatumObject(qual, isError), keys) ) {
+                // Failed to put a new item because another thread came along and put an item here first.
+                // Get the newly-put item and increment it (item is guaranteed to exist at this point)
+                table.get(keys).increment(1.0, isError);
+            }
+        }
+        else {
+            // Easy case: already an item here, so increment it
+            existingDatum.increment(1.0, isError);
+        }
+    }
+
+
+    /**
+     * creates a datum object with one observation and one or zero error
+     *
+     * @param reportedQual  the quality score reported by the instrument for this base
+     * @param isError       whether or not the observation is an error
+     * @return a new RecalDatum object with the observation and the error
+     */
+    private static RecalDatum createDatumObject(final byte reportedQual, final double isError) {
+        return new RecalDatum(1, isError, reportedQual);
+    }
 }
diff --git a/public/java/src/org/broadinstitute/sting/utils/recalibration/RecalibrationReport.java b/public/java/src/org/broadinstitute/sting/utils/recalibration/RecalibrationReport.java
index 3264677b9..a24093cd9 100644
--- a/public/java/src/org/broadinstitute/sting/utils/recalibration/RecalibrationReport.java
+++ b/public/java/src/org/broadinstitute/sting/utils/recalibration/RecalibrationReport.java
@@ -130,12 +130,12 @@ public class RecalibrationReport {
             final String covName = (String)reportTable.get(i, RecalUtils.COVARIATE_NAME_COLUMN_NAME);
             final int covIndex = optionalCovariateIndexes.get(covName);
             final Object covValue = reportTable.get(i, RecalUtils.COVARIATE_VALUE_COLUMN_NAME);
-            tempCOVarray[2] = requestedCovariates[RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.index + covIndex].keyFromValue(covValue);
+            tempCOVarray[2] = requestedCovariates[RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.ordinal() + covIndex].keyFromValue(covValue);
 
             final EventType event = EventType.eventFrom((String)reportTable.get(i, RecalUtils.EVENT_TYPE_COLUMN_NAME));
             tempCOVarray[3] = event.ordinal();
 
-            recalibrationTables.getTable(RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.index + covIndex).put(getRecalDatum(reportTable, i, false), tempCOVarray);
+            recalibrationTables.getTable(RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.ordinal() + covIndex).put(getRecalDatum(reportTable, i, false), tempCOVarray);
         }
     }
 
diff --git a/public/java/src/org/broadinstitute/sting/utils/recalibration/RecalibrationTables.java b/public/java/src/org/broadinstitute/sting/utils/recalibration/RecalibrationTables.java
index a6b1e13b9..05f711dd5 100644
--- a/public/java/src/org/broadinstitute/sting/utils/recalibration/RecalibrationTables.java
+++ b/public/java/src/org/broadinstitute/sting/utils/recalibration/RecalibrationTables.java
@@ -42,15 +42,9 @@ import java.util.ArrayList;
 
 public final class RecalibrationTables {
     public enum TableType {
-        READ_GROUP_TABLE(0),
-        QUALITY_SCORE_TABLE(1),
-        OPTIONAL_COVARIATE_TABLES_START(2);
-
-        public final int index;
-
-        private TableType(final int index) {
-            this.index = index;
-        }
+        READ_GROUP_TABLE,
+        QUALITY_SCORE_TABLE,
+        OPTIONAL_COVARIATE_TABLES_START;
     }
 
     private final ArrayList<NestedIntegerArray<RecalDatum>> tables;
@@ -60,7 +54,7 @@ public final class RecalibrationTables {
     private final PrintStream log;
 
     public RecalibrationTables(final Covariate[] covariates) {
-        this(covariates, covariates[TableType.READ_GROUP_TABLE.index].maximumKeyValue() + 1, null);
+        this(covariates, covariates[TableType.READ_GROUP_TABLE.ordinal()].maximumKeyValue() + 1, null);
     }
 
     public RecalibrationTables(final Covariate[] covariates, final int numReadGroups) {
@@ -72,31 +66,31 @@ public final class RecalibrationTables {
         for ( int i = 0; i < covariates.length; i++ )
             tables.add(i, null); // initialize so we can set below
 
-        qualDimension = covariates[TableType.QUALITY_SCORE_TABLE.index].maximumKeyValue() + 1;
+        qualDimension = covariates[TableType.QUALITY_SCORE_TABLE.ordinal()].maximumKeyValue() + 1;
         this.numReadGroups = numReadGroups;
         this.log = log;
 
-        tables.set(TableType.READ_GROUP_TABLE.index,
+        tables.set(TableType.READ_GROUP_TABLE.ordinal(),
                 log == null ? new NestedIntegerArray<RecalDatum>(numReadGroups, eventDimension) :
                         new LoggingNestedIntegerArray<RecalDatum>(log, "READ_GROUP_TABLE", numReadGroups, eventDimension));
 
-        tables.set(TableType.QUALITY_SCORE_TABLE.index, makeQualityScoreTable());
+        tables.set(TableType.QUALITY_SCORE_TABLE.ordinal(), makeQualityScoreTable());
 
-        for (int i = TableType.OPTIONAL_COVARIATE_TABLES_START.index; i < covariates.length; i++)
+        for (int i = TableType.OPTIONAL_COVARIATE_TABLES_START.ordinal(); i < covariates.length; i++)
             tables.set(i,
                     log == null ? new NestedIntegerArray<RecalDatum>(numReadGroups, qualDimension, covariates[i].maximumKeyValue()+1, eventDimension) :
-                            new LoggingNestedIntegerArray<RecalDatum>(log, String.format("OPTIONAL_COVARIATE_TABLE_%d", i - TableType.OPTIONAL_COVARIATE_TABLES_START.index + 1),
+                            new LoggingNestedIntegerArray<RecalDatum>(log, String.format("OPTIONAL_COVARIATE_TABLE_%d", i - TableType.OPTIONAL_COVARIATE_TABLES_START.ordinal() + 1),
                                     numReadGroups, qualDimension, covariates[i].maximumKeyValue()+1, eventDimension));
     }
 
     @Ensures("result != null")
     public NestedIntegerArray<RecalDatum> getReadGroupTable() {
-        return getTable(TableType.READ_GROUP_TABLE.index);
+        return getTable(TableType.READ_GROUP_TABLE.ordinal());
     }
 
     @Ensures("result != null")
     public NestedIntegerArray<RecalDatum> getQualityScoreTable() {
-        return getTable(TableType.QUALITY_SCORE_TABLE.index);
+        return getTable(TableType.QUALITY_SCORE_TABLE.ordinal());
     }
 
     @Ensures("result != null")
diff --git a/public/java/test/org/broadinstitute/sting/gatk/traversals/TraverseActiveRegionsUnitTest.java b/public/java/test/org/broadinstitute/sting/gatk/traversals/TraverseActiveRegionsUnitTest.java
index 0ec4f57f6..645f1ffc4 100644
--- a/public/java/test/org/broadinstitute/sting/gatk/traversals/TraverseActiveRegionsUnitTest.java
+++ b/public/java/test/org/broadinstitute/sting/gatk/traversals/TraverseActiveRegionsUnitTest.java
@@ -3,16 +3,10 @@ package org.broadinstitute.sting.gatk.traversals;
 import com.google.java.contract.PreconditionError;
 import net.sf.samtools.*;
 import org.broadinstitute.sting.commandline.Tags;
-import org.broadinstitute.sting.gatk.arguments.GATKArgumentCollection;
-import org.broadinstitute.sting.gatk.datasources.providers.ActiveRegionShardDataProvider;
-import org.broadinstitute.sting.gatk.datasources.providers.LocusShardDataProvider;
-import org.broadinstitute.sting.gatk.datasources.providers.ReadShardDataProvider;
-import org.broadinstitute.sting.gatk.datasources.providers.ShardDataProvider;
 import org.broadinstitute.sting.gatk.datasources.reads.*;
 import org.broadinstitute.sting.gatk.resourcemanagement.ThreadAllocation;
 import org.broadinstitute.sting.utils.GenomeLocSortedSet;
 import org.broadinstitute.sting.utils.activeregion.ActiveRegionReadState;
-import org.broadinstitute.sting.utils.activeregion.ExperimentalActiveRegionShardType;
 import org.broadinstitute.sting.utils.interval.IntervalMergingRule;
 import org.broadinstitute.sting.utils.interval.IntervalUtils;
 import org.broadinstitute.sting.utils.sam.GATKSAMRecord;
@@ -21,6 +15,7 @@ import org.broadinstitute.sting.BaseTest;
 import org.broadinstitute.sting.gatk.GenomeAnalysisEngine;
 import org.broadinstitute.sting.gatk.contexts.AlignmentContext;
 import org.broadinstitute.sting.gatk.contexts.ReferenceContext;
+import org.broadinstitute.sting.gatk.datasources.providers.LocusShardDataProvider;
 import org.broadinstitute.sting.gatk.datasources.rmd.ReferenceOrderedDataSource;
 import org.broadinstitute.sting.gatk.executive.WindowMaker;
 import org.broadinstitute.sting.gatk.refdata.RefMetaDataTracker;
@@ -33,7 +28,6 @@ import org.broadinstitute.sting.utils.fasta.CachingIndexedFastaSequenceFile;
 import org.broadinstitute.sting.utils.sam.ArtificialSAMUtils;
 import org.broadinstitute.sting.utils.sam.ReadUtils;
 import org.testng.Assert;
-import org.testng.TestException;
 import org.testng.annotations.BeforeClass;
 import org.testng.annotations.Test;
 
@@ -101,9 +95,7 @@ public class TraverseActiveRegionsUnitTest extends BaseTest {
         }
     }
 
-    private final TraverseActiveRegions<Integer, Integer> traverse = new TraverseActiveRegions<Integer, Integer>();
-    private final ExperimentalReadShardTraverseActiveRegions<Integer, Integer> readShardTraverse = new ExperimentalReadShardTraverseActiveRegions<Integer, Integer>();
-    private final ExperimentalActiveRegionShardTraverseActiveRegions<Integer, Integer> activeRegionShardTraverse = new ExperimentalActiveRegionShardTraverseActiveRegions<Integer, Integer>();
+    private final TraverseActiveRegions<Integer, Integer> t = new TraverseActiveRegions<Integer, Integer>();
 
     private IndexedFastaSequenceFile reference;
     private SAMSequenceDictionary dictionary;
@@ -114,8 +106,6 @@ public class TraverseActiveRegionsUnitTest extends BaseTest {
     private static final String testBAM = "TraverseActiveRegionsUnitTest.bam";
     private static final String testBAI = "TraverseActiveRegionsUnitTest.bai";
 
-    private static final ExperimentalActiveRegionShardType shardType = ExperimentalActiveRegionShardType.LOCUSSHARD;
-
     @BeforeClass
     private void init() throws FileNotFoundException {
         reference = new CachingIndexedFastaSequenceFile(new File(hg19Reference));
@@ -183,8 +173,8 @@ public class TraverseActiveRegionsUnitTest extends BaseTest {
 
     private List<GenomeLoc> getIsActiveIntervals(DummyActiveRegionWalker walker, List<GenomeLoc> intervals) {
         List<GenomeLoc> activeIntervals = new ArrayList<GenomeLoc>();
-        for (ShardDataProvider dataProvider : createDataProviders(intervals, testBAM)) {
-            traverse(walker, dataProvider, 0);
+        for (LocusShardDataProvider dataProvider : createDataProviders(intervals, testBAM)) {
+            t.traverse(walker, dataProvider, 0);
             activeIntervals.addAll(walker.isActiveCalls);
         }
 
@@ -421,10 +411,10 @@ public class TraverseActiveRegionsUnitTest extends BaseTest {
     }
 
     private Map<GenomeLoc, ActiveRegion> getActiveRegions(DummyActiveRegionWalker walker, List<GenomeLoc> intervals) {
-        for (ShardDataProvider dataProvider : createDataProviders(intervals, testBAM))
-            traverse(walker, dataProvider, 0);
+        for (LocusShardDataProvider dataProvider : createDataProviders(intervals, testBAM))
+            t.traverse(walker, dataProvider, 0);
 
-        endTraversal(walker, 0);
+        t.endTraversal(walker, 0);
 
         return walker.mappedActiveRegions;
     }
@@ -485,12 +475,10 @@ public class TraverseActiveRegionsUnitTest extends BaseTest {
         return record;
     }
 
-    private List<ShardDataProvider> createDataProviders(List<GenomeLoc> intervals, String bamFile) {
+    private List<LocusShardDataProvider> createDataProviders(List<GenomeLoc> intervals, String bamFile) {
         GenomeAnalysisEngine engine = new GenomeAnalysisEngine();
         engine.setGenomeLocParser(genomeLocParser);
-        GATKArgumentCollection arguments = new GATKArgumentCollection();
-        arguments.activeRegionShardType = shardType;     // make explicit
-        engine.setArguments(arguments);
+        t.initialize(engine);
 
         Collection<SAMReaderID> samFiles = new ArrayList<SAMReaderID>();
         SAMReaderID readerID = new SAMReaderID(new File(bamFile), new Tags());
@@ -498,65 +486,13 @@ public class TraverseActiveRegionsUnitTest extends BaseTest {
 
         SAMDataSource dataSource = new SAMDataSource(samFiles, new ThreadAllocation(), null, genomeLocParser);
 
-        List<ShardDataProvider> providers = new ArrayList<ShardDataProvider>();
-
-        switch (shardType) {
-            case LOCUSSHARD:
-                traverse.initialize(engine);
-                for (Shard shard : dataSource.createShardIteratorOverIntervals(new GenomeLocSortedSet(genomeLocParser, intervals), new LocusShardBalancer())) {
-                    for (WindowMaker.WindowMakerIterator window : new WindowMaker(shard, genomeLocParser, dataSource.seek(shard), shard.getGenomeLocs())) {
-                        providers.add(new LocusShardDataProvider(shard, shard.getReadProperties(), genomeLocParser, window.getLocus(), window, reference, new ArrayList<ReferenceOrderedDataSource>()));
-                    }
-                }
-                break;
-            case READSHARD:
-                readShardTraverse.initialize(engine);
-                for (Shard shard : dataSource.createShardIteratorOverIntervals(new GenomeLocSortedSet(genomeLocParser, intervals), new ReadShardBalancer())) {
-                    providers.add(new ReadShardDataProvider(shard, genomeLocParser, shard.iterator(), reference, new ArrayList<ReferenceOrderedDataSource>()));
-                }
-                break;
-            case ACTIVEREGIONSHARD:
-                activeRegionShardTraverse.initialize(engine);
-                for (Shard shard : dataSource.createShardIteratorOverIntervals(new GenomeLocSortedSet(genomeLocParser, intervals), new ActiveRegionShardBalancer())) {
-                    for (WindowMaker.WindowMakerIterator window : new WindowMaker(shard, genomeLocParser, dataSource.seek(shard), shard.getGenomeLocs())) {
-                        providers.add(new ActiveRegionShardDataProvider(shard, shard.getReadProperties(), genomeLocParser, shard.iterator(), window.getLocus(), window, reference, new ArrayList<ReferenceOrderedDataSource>()));
-                    }
-                }
-                break;
-            default: throw new TestException("Invalid shard type");
+        List<LocusShardDataProvider> providers = new ArrayList<LocusShardDataProvider>();
+        for (Shard shard : dataSource.createShardIteratorOverIntervals(new GenomeLocSortedSet(genomeLocParser, intervals), new LocusShardBalancer())) {
+            for (WindowMaker.WindowMakerIterator window : new WindowMaker(shard, genomeLocParser, dataSource.seek(shard), shard.getGenomeLocs())) {
+                providers.add(new LocusShardDataProvider(shard, shard.getReadProperties(), genomeLocParser, window.getLocus(), window, reference, new ArrayList<ReferenceOrderedDataSource>()));
+            }
         }
 
         return providers;
     }
-
-    private void traverse(DummyActiveRegionWalker walker, ShardDataProvider dataProvider, int i) {
-        switch (shardType) {
-            case LOCUSSHARD:
-                traverse.traverse(walker, (LocusShardDataProvider) dataProvider, i);
-                break;
-            case READSHARD:
-                readShardTraverse.traverse(walker, (ReadShardDataProvider) dataProvider, i);
-                break;
-            case ACTIVEREGIONSHARD:
-                activeRegionShardTraverse.traverse(walker, (ActiveRegionShardDataProvider) dataProvider, i);
-                break;
-            default: throw new TestException("Invalid shard type");
-        }
-    }
-
-    private void endTraversal(DummyActiveRegionWalker walker, int i) {
-        switch (shardType) {
-            case LOCUSSHARD:
-                traverse.endTraversal(walker, i);
-                break;
-            case READSHARD:
-                readShardTraverse.endTraversal(walker, i);
-                break;
-            case ACTIVEREGIONSHARD:
-                activeRegionShardTraverse.endTraversal(walker, i);
-                break;
-            default: throw new TestException("Invalid shard type");
-        }
-    }
-
 }
diff --git a/public/java/test/org/broadinstitute/sting/gatk/walkers/annotator/VariantAnnotatorIntegrationTest.java b/public/java/test/org/broadinstitute/sting/gatk/walkers/annotator/VariantAnnotatorIntegrationTest.java
index 90e1d5c34..b097e3d34 100755
--- a/public/java/test/org/broadinstitute/sting/gatk/walkers/annotator/VariantAnnotatorIntegrationTest.java
+++ b/public/java/test/org/broadinstitute/sting/gatk/walkers/annotator/VariantAnnotatorIntegrationTest.java
@@ -32,7 +32,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testHasAnnotsAsking1() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " -G Standard --variant " + privateTestDir + "vcfexample2.vcf -I " + validationDataLocation + "low_coverage_CEU.chr1.10k-11k.bam -L 1:10,020,000-10,021,000", 1,
-                Arrays.asList("a127623a26bac4c17c9df491e170ed88"));
+                Arrays.asList("fbfbd4d13b7ba3d76e8e186902e81378"));
         executeTest("test file has annotations, asking for annotations, #1", spec);
     }
 
@@ -40,7 +40,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testHasAnnotsAsking2() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " -G Standard --variant " + privateTestDir + "vcfexample3.vcf -I " + validationDataLocation + "NA12878.1kg.p2.chr1_10mb_11_mb.SLX.bam -L 1:10,000,000-10,050,000", 1,
-                Arrays.asList("13e24e6b9dfa241df5baa2c3f53415b9"));
+                Arrays.asList("19aef8914efc497192f89a9038310ca5"));
         executeTest("test file has annotations, asking for annotations, #2", spec);
     }
 
@@ -66,7 +66,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testNoAnnotsAsking1() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " -G Standard --variant " + privateTestDir + "vcfexample2empty.vcf -I " + validationDataLocation + "low_coverage_CEU.chr1.10k-11k.bam -L 1:10,020,000-10,021,000", 1,
-                Arrays.asList("07cb4d427235878aeec0066d7d298e54"));
+                Arrays.asList("4f0b8033da18e6cf6e9b8d5d36c21ba2"));
         executeTest("test file doesn't have annotations, asking for annotations, #1", spec);
     }
 
@@ -74,7 +74,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testNoAnnotsAsking2() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " -G Standard --variant " + privateTestDir + "vcfexample3empty.vcf -I " + validationDataLocation + "NA12878.1kg.p2.chr1_10mb_11_mb.SLX.bam -L 1:10,000,000-10,050,000", 1,
-                Arrays.asList("e579097677d5e56a5776151251947961"));
+                Arrays.asList("64ca176d587dfa2b3b9dec9f7999305c"));
         executeTest("test file doesn't have annotations, asking for annotations, #2", spec);
     }
 
@@ -82,7 +82,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testExcludeAnnotations() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " -G Standard -XA FisherStrand -XA ReadPosRankSumTest --variant " + privateTestDir + "vcfexample2empty.vcf -I " + validationDataLocation + "low_coverage_CEU.chr1.10k-11k.bam -L 1:10,020,000-10,021,000", 1,
-                Arrays.asList("348314945436ace71ce6b1a52559d9ee"));
+                Arrays.asList("f33f417fad98c05d9cd08ffa22943b0f"));
         executeTest("test exclude annotations", spec);
     }
 
@@ -90,7 +90,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testOverwritingHeader() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " -G Standard --variant " + privateTestDir + "vcfexample4.vcf -I " + validationDataLocation + "NA12878.1kg.p2.chr1_10mb_11_mb.SLX.bam -L 1:10,001,292", 1,
-                Arrays.asList("ae7930e37a66c0aa4cfe0232736864fe"));
+                Arrays.asList("0c810f6c4abef9d9dc5513ca872d3d22"));
         executeTest("test overwriting header", spec);
     }
 
@@ -98,7 +98,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testNoReads() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " -G Standard --variant " + privateTestDir + "vcfexample3empty.vcf -L " + privateTestDir + "vcfexample3empty.vcf", 1,
-                Arrays.asList("a0ba056c2625033e5e859fd6bcec1256"));
+                Arrays.asList("1c423b7730b9805e7b885ece924286e0"));
         executeTest("not passing it any reads", spec);
     }
 
@@ -106,7 +106,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testDBTagWithDbsnp() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " --dbsnp " + b36dbSNP129 + " -G Standard --variant " + privateTestDir + "vcfexample3empty.vcf -L " + privateTestDir + "vcfexample3empty.vcf", 1,
-                Arrays.asList("0be7da17340111a94e8581ee3808c88a"));
+                Arrays.asList("54d7d5bb9404652857adf5e50d995f30"));
         executeTest("getting DB tag with dbSNP", spec);
     }
 
@@ -114,7 +114,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testMultipleIdsWithDbsnp() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " --alwaysAppendDbsnpId --dbsnp " + b36dbSNP129 + " -G Standard --variant " + privateTestDir + "vcfexample3withIDs.vcf -L " + privateTestDir + "vcfexample3withIDs.vcf", 1,
-                Arrays.asList("e40e625302a496ede42eed61c2ce524b"));
+                Arrays.asList("5fe63e511061ed4f91d938e72e7e3c39"));
         executeTest("adding multiple IDs with dbSNP", spec);
     }
 
@@ -122,7 +122,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testDBTagWithHapMap() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " --comp:H3 " + privateTestDir + "fakeHM3.vcf -G Standard --variant " + privateTestDir + "vcfexample3empty.vcf -L " + privateTestDir + "vcfexample3empty.vcf", 1,
-                Arrays.asList("cb50876477d3e035b6eda5d720d7ba8d"));
+                Arrays.asList("cc7184263975595a6e2473d153227146"));
         executeTest("getting DB tag with HM3", spec);
     }
 
@@ -130,7 +130,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testNoQuals() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " --variant " + privateTestDir + "noQual.vcf -I " + validationDataLocation + "NA12878.1kg.p2.chr1_10mb_11_mb.SLX.bam -L " + privateTestDir + "noQual.vcf -A QualByDepth", 1,
-                Arrays.asList("458412261d61797d39f802c1e03d63f6"));
+                Arrays.asList("aea983adc01cd059193538cc30adc17d"));
         executeTest("test file doesn't have QUALs", spec);
     }
 
@@ -138,7 +138,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testUsingExpression() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " --resource:foo " + privateTestDir + "targetAnnotations.vcf -G Standard --variant " + privateTestDir + "vcfexample3empty.vcf -E foo.AF -L " + privateTestDir + "vcfexample3empty.vcf", 1,
-                Arrays.asList("39defa8108dca9fa3e54b22a7da43f77"));
+                Arrays.asList("2b0e8cdfd691779befc5ac123d1a1887"));
         executeTest("using expression", spec);
     }
 
@@ -146,7 +146,7 @@ public class VariantAnnotatorIntegrationTest extends WalkerTest {
     public void testUsingExpressionWithID() {
         WalkerTestSpec spec = new WalkerTestSpec(
                 baseTestString() + " --resource:foo " + privateTestDir + "targetAnnotations.vcf -G Standard --variant " + privateTestDir + "vcfexample3empty.vcf -E foo.ID -L " + privateTestDir + "vcfexample3empty.vcf", 1,
-                Arrays.asList("a917edd58a0c235e9395bfc2d2020a8c"));
+                Arrays.asList("3de1d1998203518098ffae233f3e2352"));
         executeTest("using expression with ID", spec);
     }
 
diff --git a/public/java/test/org/broadinstitute/sting/utils/progressmeter/ProgressMeterDaemonUnitTest.java b/public/java/test/org/broadinstitute/sting/utils/progressmeter/ProgressMeterDaemonUnitTest.java
index 420db683e..5c6c675a7 100644
--- a/public/java/test/org/broadinstitute/sting/utils/progressmeter/ProgressMeterDaemonUnitTest.java
+++ b/public/java/test/org/broadinstitute/sting/utils/progressmeter/ProgressMeterDaemonUnitTest.java
@@ -96,7 +96,11 @@ public class ProgressMeterDaemonUnitTest extends BaseTest {
         daemon.done();
         Assert.assertTrue(daemon.isDone());
 
-        Assert.assertEquals(meter.progressCalls.size(), ticks,
-                "Expected " + ticks + " progress calls from daemon thread, but only got " + meter.progressCalls.size() + " with exact calls " + meter.progressCalls);
+        Assert.assertTrue(meter.progressCalls.size() >= 1,
+                "Expected at least one progress update call from daemon thread, but only got " + meter.progressCalls.size() + " with exact calls " + meter.progressCalls);
+
+        final int tolerance = (int)Math.ceil(0.8 * meter.progressCalls.size());
+        Assert.assertTrue(Math.abs(meter.progressCalls.size() - ticks) <= tolerance,
+                "Expected " + ticks + " progress calls from daemon thread, but got " + meter.progressCalls.size() + " and a tolerance of only " + tolerance);
     }
 }
diff --git a/public/java/test/org/broadinstitute/sting/utils/recalibration/RecalibrationReportUnitTest.java b/public/java/test/org/broadinstitute/sting/utils/recalibration/RecalibrationReportUnitTest.java
index f95fae464..be8e3a077 100644
--- a/public/java/test/org/broadinstitute/sting/utils/recalibration/RecalibrationReportUnitTest.java
+++ b/public/java/test/org/broadinstitute/sting/utils/recalibration/RecalibrationReportUnitTest.java
@@ -94,8 +94,8 @@ public class RecalibrationReportUnitTest {
                 qualTable.put(createRandomRecalDatum(randomMax, 10), covariates[0], covariates[1], errorMode.ordinal());
                 nKeys += 2;
                 for (int j = 0; j < optionalCovariates.size(); j++) {
-                    final NestedIntegerArray<RecalDatum> covTable = recalibrationTables.getTable(RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.index + j);
-                    final int covValue = covariates[RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.index + j];
+                    final NestedIntegerArray<RecalDatum> covTable = recalibrationTables.getTable(RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.ordinal() + j);
+                    final int covValue = covariates[RecalibrationTables.TableType.OPTIONAL_COVARIATE_TABLES_START.ordinal() + j];
                     if ( covValue >= 0 ) {
                         covTable.put(createRandomRecalDatum(randomMax, 10), covariates[0], covariates[1], covValue, errorMode.ordinal());
                         nKeys++;
diff --git a/public/java/test/org/broadinstitute/sting/utils/recalibration/RecalibrationTablesUnitTest.java b/public/java/test/org/broadinstitute/sting/utils/recalibration/RecalibrationTablesUnitTest.java
index 93e52ae83..7a947a539 100644
--- a/public/java/test/org/broadinstitute/sting/utils/recalibration/RecalibrationTablesUnitTest.java
+++ b/public/java/test/org/broadinstitute/sting/utils/recalibration/RecalibrationTablesUnitTest.java
@@ -29,15 +29,46 @@ import org.broadinstitute.sting.BaseTest;
 import org.broadinstitute.sting.utils.collections.NestedIntegerArray;
 import org.broadinstitute.sting.utils.recalibration.covariates.*;
 import org.testng.Assert;
+import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;
 
+import java.util.Arrays;
+import java.util.List;
+
 public final class RecalibrationTablesUnitTest extends BaseTest {
+    private RecalibrationTables tables;
+    private Covariate[] covariates;
+    private int numReadGroups = 6;
+    final byte qualByte = 1;
+    final List<Integer> combineStates = Arrays.asList(0, 1, 2);
+
+    @BeforeMethod
+    private void makeTables() {
+        covariates = RecalibrationTestUtils.makeInitializedStandardCovariates();
+        tables = new RecalibrationTables(covariates, numReadGroups);
+        fillTable(tables);
+    }
+
+    private void fillTable(final RecalibrationTables tables) {
+        for ( int iterations = 0; iterations < 10; iterations++ ) {
+            for ( final EventType et : EventType.values() ) {
+                for ( final int rg : combineStates) {
+                    final double error = rg % 2 == 0 ? 1 : 0;
+                    RecalUtils.incrementDatumOrPutIfNecessary(tables.getReadGroupTable(), qualByte, error, rg, et.ordinal());
+                    for ( final int qual : combineStates) {
+                        RecalUtils.incrementDatumOrPutIfNecessary(tables.getQualityScoreTable(), qualByte, error, rg, qual, et.ordinal());
+                        for ( final int cycle : combineStates)
+                            RecalUtils.incrementDatumOrPutIfNecessary(tables.getTable(2), qualByte, error, rg, qual, cycle, et.ordinal());
+                        for ( final int context : combineStates)
+                            RecalUtils.incrementDatumOrPutIfNecessary(tables.getTable(3), qualByte, error, rg, qual, context, et.ordinal());
+                    }
+                }
+            }
+        }
+    }
+
     @Test
     public void basicTest() {
-        final Covariate[] covariates = RecalibrationTestUtils.makeInitializedStandardCovariates();
-        final int numReadGroups = 6;
-        final RecalibrationTables tables = new RecalibrationTables(covariates, numReadGroups);
-
         final Covariate qualCov = covariates[1];
         final Covariate cycleCov = covariates[2];
         final Covariate contextCov = covariates[3];
@@ -45,11 +76,11 @@ public final class RecalibrationTablesUnitTest extends BaseTest {
         Assert.assertEquals(tables.numTables(), covariates.length);
 
         Assert.assertNotNull(tables.getReadGroupTable());
-        Assert.assertEquals(tables.getReadGroupTable(), tables.getTable(RecalibrationTables.TableType.READ_GROUP_TABLE.index));
+        Assert.assertEquals(tables.getReadGroupTable(), tables.getTable(RecalibrationTables.TableType.READ_GROUP_TABLE.ordinal()));
         testDimensions(tables.getReadGroupTable(), numReadGroups);
 
         Assert.assertNotNull(tables.getQualityScoreTable());
-        Assert.assertEquals(tables.getQualityScoreTable(), tables.getTable(RecalibrationTables.TableType.QUALITY_SCORE_TABLE.index));
+        Assert.assertEquals(tables.getQualityScoreTable(), tables.getTable(RecalibrationTables.TableType.QUALITY_SCORE_TABLE.ordinal()));
         testDimensions(tables.getQualityScoreTable(), numReadGroups, qualCov.maximumKeyValue() + 1);
 
         Assert.assertNotNull(tables.getTable(2));
@@ -72,13 +103,74 @@ public final class RecalibrationTablesUnitTest extends BaseTest {
 
     @Test
     public void basicMakeQualityScoreTable() {
-        final Covariate[] covariates = RecalibrationTestUtils.makeInitializedStandardCovariates();
-        final int numReadGroups = 6;
-        final RecalibrationTables tables = new RecalibrationTables(covariates, numReadGroups);
-
         final Covariate qualCov = covariates[1];
         final NestedIntegerArray<RecalDatum> copy = tables.makeQualityScoreTable();
         testDimensions(copy, numReadGroups, qualCov.maximumKeyValue()+1);
         Assert.assertEquals(copy.getAllValues().size(), 0);
     }
+
+    @Test
+    public void testCombine1() {
+        final RecalibrationTables merged = new RecalibrationTables(covariates, numReadGroups);
+        fillTable(merged);
+
+        merged.combine(tables);
+
+        for ( int i = 0; i < tables.numTables(); i++ ) {
+            NestedIntegerArray<RecalDatum> table = tables.getTable(i);
+            NestedIntegerArray<RecalDatum> mergedTable = merged.getTable(i);
+
+            Assert.assertEquals(table.getAllLeaves().size(), mergedTable.getAllLeaves().size());
+            for ( final NestedIntegerArray.Leaf<RecalDatum> leaf : table.getAllLeaves() ) {
+                final RecalDatum mergedValue = mergedTable.get(leaf.keys);
+                Assert.assertNotNull(mergedValue);
+                Assert.assertEquals(mergedValue.getNumObservations(), leaf.value.getNumObservations() * 2);
+                Assert.assertEquals(mergedValue.getNumMismatches(), leaf.value.getNumMismatches() * 2);
+            }
+        }
+    }
+
+    @Test
+    public void testCombineEmptyOther() {
+        final RecalibrationTables merged = new RecalibrationTables(covariates, numReadGroups);
+
+        merged.combine(tables);
+
+        for ( int i = 0; i < tables.numTables(); i++ ) {
+            NestedIntegerArray<RecalDatum> table = tables.getTable(i);
+            NestedIntegerArray<RecalDatum> mergedTable = merged.getTable(i);
+
+            Assert.assertEquals(table.getAllLeaves().size(), mergedTable.getAllLeaves().size());
+            for ( final NestedIntegerArray.Leaf<RecalDatum> leaf : table.getAllLeaves() ) {
+                final RecalDatum mergedValue = mergedTable.get(leaf.keys);
+                Assert.assertNotNull(mergedValue);
+                Assert.assertEquals(mergedValue.getNumObservations(), leaf.value.getNumObservations());
+                Assert.assertEquals(mergedValue.getNumMismatches(), leaf.value.getNumMismatches());
+            }
+        }
+    }
+
+    @Test
+    public void testCombinePartial() {
+        final RecalibrationTables merged = new RecalibrationTables(covariates, numReadGroups);
+        for ( final int rg : combineStates) {
+            RecalUtils.incrementDatumOrPutIfNecessary(merged.getTable(3), qualByte, 1, rg, 0, 0, 0);
+        }
+
+        merged.combine(tables);
+        for ( int i = 0; i < tables.numTables(); i++ ) {
+            NestedIntegerArray<RecalDatum> table = tables.getTable(i);
+            NestedIntegerArray<RecalDatum> mergedTable = merged.getTable(i);
+
+            Assert.assertEquals(table.getAllLeaves().size(), mergedTable.getAllLeaves().size());
+            for ( final NestedIntegerArray.Leaf<RecalDatum> leaf : table.getAllLeaves() ) {
+                final RecalDatum mergedValue = mergedTable.get(leaf.keys);
+                Assert.assertNotNull(mergedValue);
+
+                final int delta = i == 3 && leaf.keys[1] == 0 && leaf.keys[2] == 0 && leaf.keys[3] == 0 ? 1 : 0;
+                Assert.assertEquals(mergedValue.getNumObservations(), leaf.value.getNumObservations() + delta);
+                Assert.assertEquals(mergedValue.getNumMismatches(), leaf.value.getNumMismatches() + delta);
+            }
+        }
+    }
 }