diff --git a/checkin_notes b/checkin_notes
index c35ec336f3..98a510bf0f 100644
--- a/checkin_notes
+++ b/checkin_notes
@@ -7391,3 +7391,22 @@ Rom    17 Oct 2011
         background_image.png
     clientgui/skins/Default/
         skin.xml
+
+David  18 Oct 2011
+    - backend API: added function cancel_jobs(minid, maxid)
+        for canceling jobs
+    - added program cancel_jobs for canceling jobs
+    - DB interface: it's not an error if update_fields_noid()
+        affects != 1 rows
+
+    db/
+        db_base.cpp
+    tools/
+        backend_lib.cpp,h
+        cancel_jobs.cpp (new)
+        poll_wu.cpp
+        Makefile.am
+    lib/
+        parse.cpp
+    py/Boinc/
+        setup_project.py
diff --git a/db/db_base.cpp b/db/db_base.cpp
index 21eef6740f..0ca99f9ab9 100644
--- a/db/db_base.cpp
+++ b/db/db_base.cpp
@@ -329,7 +329,6 @@ int DB_BASE::update_fields_noid(char* set_clause, char* where_clause) {
     );
     int retval = db->do_query(query);
     if (retval) return retval;
-    if (db->affected_rows() != 1) return ERR_DB_NOT_FOUND;
     return 0;
 }
 
diff --git a/doc/sim/sim_web.php b/doc/sim/sim_web.php
index a497a8d386..56d18c8278 100644
--- a/doc/sim/sim_web.php
+++ b/doc/sim/sim_web.php
@@ -75,12 +75,10 @@ function show_scenario_summary($f) {
 function show_scenarios() {
     page_head("The BOINC Client Emulator");
     echo "
-        Welcome to the BOINC Client Emulator (BCE).
-        BCE <b>emulates</b> a BOINC client attached to one or more projects.
+        The BOINC Client Emulator (BCE)
+        <b>emulates</b> a BOINC client attached to one or more projects.
         It predicts, in a few seconds,
-        what the BOINC client will do over a period of day or months.
-        This lets you predict how future versions of BOINC
-        will perform on your computers.
+        what the latest BOINC client will do over a period of day or months.
         By reporting problem situations to BOINC developers,
         you can help us fix bugs and improve performance.
         <h3>Scenarios</h3>
@@ -92,37 +90,33 @@ function show_scenarios() {
           Any projects that don't currently have tasks are ignored.
         <li> <b>global_prefs.xml</b> and <b>global_prefs_override.xml</b>:
             computing preferences (optional).
+        <li> <b>cc_config.xml</b>: options such as GPU exclusions
         </ul>
+        You create a scenario by uploading these files
+        using the <b>Create a scenario</b> button below.
         You can use the files from a running BOINC client
         to emulate that client.
-        You can modify these files, or create new ones, to study hypothetical scenarios
+        <p>
+        You can modify these files, or create new ones,
+        to study hypothetical scenarios
         (e.g. hosts with a large number of CPUs,
         hosts attached to a large number of projects,
         projects with very short or long jobs, and so on).
         See <a href=http://boinc.berkeley.edu/trac/wiki/ClientSim>The
         BCE documentation</a> for details.
-        <p>
-        You create a scenario by uploading these files to the BOINC server.
         <h3>Simulations</h3>
         You can run <b>simulations</b> based on existing scenarios
         (including scenarios created by other people).
         The parameters of a simulation include
         <ul>
         <li> The duration and time resolution of the simulation.
-        <li> Choices for various client policy alternatives, including:
-            <ul>
-            <li>Whether to use Recent Estimated Credit scheduling
-                (the proposed policy for the 6.14 client)
-            <li>Whether to use Hysteresis-based work fetch
-                (the proposed policy for the 6.14 client)
-            </ul>
-        <li> log flags
+        <li> Log flags
         </ul>
         The outputs of a simulation include
         <ul>
         <li> A 'time line' showing CPU and GPU usage.
         <li> The client's message log
-        <li> graphs of scheduling-related data (debt, REC).
+        <li> graphs of scheduling-related data (REC).
         <li> A summary of several <b>figures of merit</b>, including
             <ul>
             <li>idle fraction: the fraction of processing power that was unused
@@ -140,14 +134,17 @@ function show_scenarios() {
         made bad scheduling or work-fetch decisions.
         Or you find may places where the simulator doesn't
         seem to be working correctly.
-        <p>
         In such cases, please add a <b>comment</b> to the simulation,
         indicating the nature of the problem
         and the simulation time when it occurred.
         <p>
-        Also, please post to the <a href=http://lists.ssl.berkeley.edu/mailman/listinfo/boinc_dev>boinc_dev</a> email list
-        if you have problems using BCE,
-        or if you have suggestions for new features.
+        Please post to the <a href=http://lists.ssl.berkeley.edu/mailman/listinfo/boinc_dev>boinc_dev</a> email list if
+        <ul>
+        <li> a simulation reveals a bug or bad scheduling decision
+        <li> you have problems using BCE
+        <li> BCE doesn't do more or less the same thing as your client
+        <li> you have suggestions for new features.
+        </ul>
         <hr>
     ";
     show_button(
diff --git a/lib/parse.cpp b/lib/parse.cpp
index b3f4611f29..3587e86b30 100644
--- a/lib/parse.cpp
+++ b/lib/parse.cpp
@@ -438,10 +438,10 @@ void xml_unescape(char* buf) {
             *out++ = c;
             p = strchr(in, ';');
             if (p) {
-	      in=p+1; 
-	    } else {
-	      while (isdigit(*in)) in++;
-	    }
+                in = p+1; 
+            } else {
+                while (isdigit(*in)) in++;
+            }
         } else {
             *out++ = *in++;
         }
diff --git a/py/Boinc/setup_project.py b/py/Boinc/setup_project.py
index efaecdd128..27fa4ba753 100644
--- a/py/Boinc/setup_project.py
+++ b/py/Boinc/setup_project.py
@@ -384,7 +384,7 @@ sys.path.insert(0, os.path.join('%s', 'py'))
         [ 'appmgr', 'create_work', 'xadd', 'dbcheck_files_exist', 'run_in_ops',
           'update_versions', 'parse_config', 'grep_logs', 'db_query',
           'watch_tcp', 'sign_executable', 'dir_hier_move',
-          'manage_privileges',
+          'manage_privileges', 'cancel_jobs',
           'dir_hier_path', 'boinc_submit', 'demo_submit', 'demo_query' ])
     map(lambda (s): install(srcdir('lib',s), dir('bin',s)),
         [ 'crypt_prog' ])
diff --git a/tools/Makefile.am b/tools/Makefile.am
index 564d35d3e6..f80b5f9a83 100644
--- a/tools/Makefile.am
+++ b/tools/Makefile.am
@@ -3,7 +3,7 @@ include $(top_srcdir)/Makefile.incl
 
 scheddir = $(libexecdir)/sched
 
-bin_PROGRAMS = create_work sign_executable dir_hier_path dir_hier_move
+bin_PROGRAMS = create_work sign_executable dir_hier_path dir_hier_move cancel_jobs
 
 dist_bin_SCRIPTS = \
 	    boinc_submit \
@@ -26,6 +26,9 @@ dist_sched_SCRIPTS = \
 AM_CXXFLAGS += $(MYSQL_CFLAGS)
 AM_LDFLAGS += -static
 
+cancel_jobs_SOURCES = cancel_jobs.cpp
+cancel_jobs_LDADD = $(SERVERLIBS)
+
 create_work_SOURCES = create_work.cpp
 create_work_LDADD = $(SERVERLIBS)
 
diff --git a/tools/backend_lib.cpp b/tools/backend_lib.cpp
index 215a6165d9..21b1aad6f1 100644
--- a/tools/backend_lib.cpp
+++ b/tools/backend_lib.cpp
@@ -464,4 +464,28 @@ int put_file(
     return 0;
 }
 
+int cancel_jobs(int min_id, int max_id) {
+    DB_WORKUNIT wu;
+    DB_RESULT result;
+    char set_clause[256], where_clause[256];
+    int retval;
+
+    sprintf(set_clause, "server_state=%d, outcome=%d",
+        RESULT_SERVER_STATE_OVER, RESULT_OUTCOME_DIDNT_NEED
+    );
+    sprintf(where_clause, "server_state=%d and workunitid >=%d and workunitid<= %d",
+        RESULT_SERVER_STATE_UNSENT, min_id, max_id
+    );
+    retval = result.update_fields_noid(set_clause, where_clause);
+    if (retval) return retval;
+
+    sprintf(set_clause, "error_mask=error_mask|%d, transition_time=%d",
+        WU_ERROR_CANCELLED, (int)(time(0))
+    );
+    sprintf(where_clause, "id>=%d and id<=%d", min_id, max_id);
+    retval = wu.update_fields_noid(set_clause, where_clause);
+    if (retval) return retval;
+    return 0;
+}
+
 const char *BOINC_RCSID_b5f8b10eb5 = "$Id$";
diff --git a/tools/backend_lib.h b/tools/backend_lib.h
index f5154fa3bf..1d6f315ee7 100644
--- a/tools/backend_lib.h
+++ b/tools/backend_lib.h
@@ -86,4 +86,8 @@ extern int get_file(
     R_RSA_PRIVATE_KEY& key
 );
 
+// cancel jobs from min_id to max_id inclusive
+//
+extern int cancel_jobs(int min_id, int max_id);
+
 #endif
diff --git a/tools/cancel_jobs.cpp b/tools/cancel_jobs.cpp
new file mode 100644
index 0000000000..c2e1588c70
--- /dev/null
+++ b/tools/cancel_jobs.cpp
@@ -0,0 +1,54 @@
+// This file is part of BOINC.
+// http://boinc.berkeley.edu
+// Copyright (C) 2011 University of California
+//
+// BOINC is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License
+// as published by the Free Software Foundation,
+// either version 3 of the License, or (at your option) any later version.
+//
+// BOINC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with BOINC.  If not, see <http://www.gnu.org/licenses/>.
+
+// cancel_jobs min-ID max-ID
+//
+// cancel jobs from min-ID to max-ID inclusive
+
+#include <stdio.h>
+
+#include "backend_lib.h"
+#include "sched_config.h"
+
+void usage() {
+    fprintf(stderr, "Usage: cancel_jobs min-ID max-ID\n");
+    exit(1);
+}
+
+int main(int argc, char** argv) {
+    if (argc != 3) usage();
+    int min_id = atoi(argv[1]);
+    int max_id = atoi(argv[2]);
+    if (!min_id || !max_id) usage();
+
+    int retval = config.parse_file();
+    if (retval) exit(1);
+
+    retval = boinc_db.open(
+        config.db_name, config.db_host, config.db_user, config.db_passwd
+    );
+    if (retval) {
+        printf("boinc_db.open: %s\n", boincerror(retval));
+        exit(1);
+    }
+
+    retval = cancel_jobs(min_id, max_id);
+    if (retval) {
+        fprintf(stderr, "cancel_jobs() failed: %s\n", boincerror(retval));
+        exit(retval);
+    }
+}
diff --git a/tools/poll_wu.cpp b/tools/poll_wu.cpp
index 0142d7ddf6..2be64f9f37 100644
--- a/tools/poll_wu.cpp
+++ b/tools/poll_wu.cpp
@@ -15,18 +15,18 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with BOINC.  If not, see <http://www.gnu.org/licenses/>.
 
-//a program for polling the status of a WU in the BOINC
-//system this is needed for integration with GRID.
+// a program for polling the status of a WU in the BOINC
+// system this is needed for integration with GRID.
 //
-//the states have  to be the of the type the GRAM framework supplies:
-//Globus::GRAM::JobState
+// the states have  to be the of the type the GRAM framework supplies:
+// Globus::GRAM::JobState
 //
-//Pending: 1
-//Active: 2
-//Done: 3
-//Failed: 4
-//Suspended: 5
-//Unsubmitted: 6
+// Pending: 1
+// Active: 2
+// Done: 3
+// Failed: 4
+// Suspended: 5
+// Unsubmitted: 6
 //
 //
 // Author: Christian Soettrup