diff --git a/api/boinc_api.C b/api/boinc_api.C
index 5eb4a3ce92..c14ee53cae 100644
--- a/api/boinc_api.C
+++ b/api/boinc_api.C
@@ -444,12 +444,15 @@ int boinc_finish(int status) {
 // Win: called from the worker or timer thread.
 //
 // make static eventually
+//
 void boinc_exit(int status) {
     if (options.backwards_compatible_graphics) {
         graphics_cleanup();
     }
     
-    file_lock.unlock(LOCKFILE);
+    if (options.main_program) {
+        file_lock.unlock(LOCKFILE);
+    }
 
     fflush(NULL);
 
@@ -461,7 +464,7 @@ void boinc_exit(int status) {
     //
     BOINCINFO("Exit Status: %d", status);
 #if   defined(_WIN32)
-    // Halts all the threads and then cleans up.
+    // Halt all the threads and cleans up.
     TerminateProcess(GetCurrentProcess(), status);
 #elif defined(__APPLE_CC__)
     // stops endless exit()/atexit() loops.
diff --git a/checkin_notes b/checkin_notes
index 96a7d7b1f1..f92ab8a7c6 100644
--- a/checkin_notes
+++ b/checkin_notes
@@ -7638,3 +7638,34 @@ David  22 Sept 2008
             update_profile_pages.php
         user/
             language_select.php
+
+David  22 Sept 2008
+    - API: in boinc_exit(), release the lockfile only if
+        we're the main program (otherwise we didn't lock it in
+        the first place, and a crash results).  From Artyom Sharov.
+    - scheduler: add support for the GCL simulator,
+        which uses special versions of backend programs
+        that use virtual time,
+        and that wait for signals instead of sleep()ing.
+
+        To compile:
+            make clean
+            configure CXXFLAGS="-DGCL_SIMULATOR"
+            make
+
+    api/
+        boinc_api.C
+    db/
+        boinc_db.C,h
+    lib/
+        util.C,h
+    sched/
+        feeder.C
+        hr_info.C
+        pymw_assimilator.C
+        sched_util.C,h
+        transitioner.C
+        trickle_handler.C
+        validator.C
+    tools/
+        backend_lib.C
diff --git a/db/boinc_db.C b/db/boinc_db.C
index 32f42f1549..9da647be86 100644
--- a/db/boinc_db.C
+++ b/db/boinc_db.C
@@ -29,6 +29,7 @@
 #endif
 
 #include "str_util.h"
+#include "util.h"
 #include "error_numbers.h"
 #include "boinc_db.h"
 
@@ -921,7 +922,7 @@ void DB_CREDIT_MULTIPLIER::db_print(char* buf) {
         "time=%d, "
         "multiplier=%f ",
         appid,
-        time,
+        _time,
         multiplier
     );
 }
@@ -931,7 +932,7 @@ void DB_CREDIT_MULTIPLIER::db_parse(MYSQL_ROW& r) {
     clear();
     id = atoi(r[i++]);
     appid = atoi(r[i++]);
-    time = atoi(r[i++]);
+    _time = atoi(r[i++]);
     multiplier = atof(r[i++]);
 }
 
@@ -943,7 +944,7 @@ void DB_CREDIT_MULTIPLIER::get_nearest(int _appid, int t) {
     // set default values.
     clear();
     multiplier = 1;
-    time = ::time(NULL);
+    _time = time(0);
     appid = _appid;
 
     snprintf(query,MAX_QUERY_LEN,
diff --git a/db/boinc_db.h b/db/boinc_db.h
index 33092be2a3..444cbb737a 100644
--- a/db/boinc_db.h
+++ b/db/boinc_db.h
@@ -566,7 +566,7 @@ struct TRANSITIONER_ITEM {
 struct CREDIT_MULTIPLIER {
     int id;
     int appid;
-    int time;
+    int _time;
     double multiplier;
 
     void clear();
diff --git a/doc/boinc_news.php b/doc/boinc_news.php
index 7be6499cc7..a6541358df 100644
--- a/doc/boinc_news.php
+++ b/doc/boinc_news.php
@@ -1,6 +1,11 @@
 <?
 
 $project_news = array(
+array("September 20, 2008",
+    "Welcome back to <a href=http://docking.cis.udel.edu/>Docking@Home</a>,
+    a project at the University of Delaware that studies
+    protein-ligand interactions (and BOINC itself)."
+),
 array("September 15, 2008",
     "<a href=http://forja.unex.es/projects/ogm>OGM (Organizational Grid Manager)</a>
     has been released by the University of Extremadura.
diff --git a/doc/projects.inc b/doc/projects.inc
index 8d27193eda..1122f49603 100644
--- a/doc/projects.inc
+++ b/doc/projects.inc
@@ -3,6 +3,14 @@
 $biomed = array(
     "Biology and Medicine",
     array(
+        array(
+            "Docking@Home",
+            "http://docking.cis.udel.edu/",
+            "University of Delaware",
+            "Study of protein - ligand interactions",
+            "Docking@Home has both bioscience and computer science goals. The project aims to further knowledge of the atomic details of protein-ligand interactions and, by doing so, will search for insights into the discovery of novel pharmaceuticals.",
+            "docking.png"
+        ),
         array(
             "GPU Grid - PS3 Grid",
             "http://www.ps3grid.net/",
@@ -194,14 +202,14 @@ $math = array(
             "Find all the generalized binary number systems (in which bases are matrices and digits are vectors) up to dimension 11.",
             "szdg1_small.jpg"
         ),
-        array(
-            "Riesel Sieve",
-            "http://boinc.rieselsieve.com/",
-            "Riesel Sieve community",
-            "Mathematics",
-            "Find prime numbers of the form k*2<sup>n</sup>-1",
-            ""
-        ),
+//        array(
+//            "Riesel Sieve",
+//            "http://boinc.rieselsieve.com/",
+//            "Riesel Sieve community",
+//            "Mathematics",
+//            "Find prime numbers of the form k*2<sup>n</sup>-1",
+//            ""
+//        ),
         array(
             "Rectilinear Crossing Number",
             "http://dist.ist.tugraz.at/cape5/",
diff --git a/lib/util.C b/lib/util.C
index a34f97c33a..09eb4a7ef6 100644
--- a/lib/util.C
+++ b/lib/util.C
@@ -62,9 +62,16 @@ using std::vector;
 #define EPOCHFILETIME_SEC (11644473600.)
 #define TEN_MILLION 10000000.
 
+#ifdef GCL_SIMULATOR
+double simtime;
+#endif
+
 // return time of day (seconds since 1970) as a double
 //
 double dtime() {
+#ifdef GCL_SIMULATOR
+    return simtime;
+#else
 #ifdef _WIN32
     LARGE_INTEGER time;
     FILETIME sysTime;
@@ -81,6 +88,7 @@ double dtime() {
     gettimeofday(&tv, 0);
     return tv.tv_sec + (tv.tv_usec/1.e6);
 #endif
+#endif
 }
 
 // return time today 0:00 in seconds since 1970 as a double
diff --git a/lib/util.h b/lib/util.h
index 83c1e32b3c..2b52c4a1dd 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -93,4 +93,10 @@ extern bool process_exists(int);
 #endif
 
 extern int wait_client_mutex(const char* dir, double timeout);
+
+#ifdef GCL_SIMULATOR
+extern double simtime;
+#define time(x) ((int)simtime)
+#endif
+
 #endif
diff --git a/tools/backend_lib.C b/tools/backend_lib.C
index 512d87dddc..e7652a8d16 100644
--- a/tools/backend_lib.C
+++ b/tools/backend_lib.C
@@ -35,6 +35,7 @@
 #include "common_defs.h"
 #include "filesys.h"
 #include "sched_util.h"
+#include "util.h"
 
 #include "backend_lib.h"