diff --git a/api/boinc_api.C b/api/boinc_api.C
index d633c4ca1b..9f0f47b2de 100644
--- a/api/boinc_api.C
+++ b/api/boinc_api.C
@@ -56,6 +56,7 @@ using namespace std;
 // Unless otherwise noted, "CPU time" refers to the sum over all episodes
 // (not counting the part after the last checkpoint in an episode).
 
+static pthread_t timer_thread_handle;
 static APP_INIT_DATA aid;
 static FILE_LOCK file_lock;
 APP_CLIENT_SHM* app_client_shm = 0;
@@ -594,6 +595,17 @@ static void worker_timer(int /*a*/) {
 #endif
 }
 
+#ifndef _USECONDS_T_DECLARED
+typedef unsigned int useconds_t;
+#endif
+
+void * timer_thread(void *) {
+    while(1) {
+        usleep((useconds_t)(TIMER_PERIOD*1000000));
+        worker_timer(0);
+    }
+    /*NOTREACHED*/
+}
 
 // set up a periodic timer interrupt for the worker thread.
 // This is called only and always by the worker thread
@@ -626,6 +638,12 @@ int set_worker_timer() {
     // lower our priority here
     //
     SetThreadPriority(worker_thread_handle, THREAD_PRIORITY_IDLE);
+#else
+#if 1
+    retval = pthread_create(&timer_thread_handle, NULL, timer_thread, NULL);
+    if (retval) {
+        perror("set_worker_timer(): pthread_create(): %d");
+    }
 #else
     struct sigaction sa;
     itimerval value;
@@ -643,6 +661,7 @@ int set_worker_timer() {
     if (retval) {
         perror("boinc set_worker_timer() setitimer");
     }
+#endif
 #endif
     return retval;
 }
diff --git a/checkin_notes b/checkin_notes
index 5aa5b9136b..9f41df913d 100755
--- a/checkin_notes
+++ b/checkin_notes
@@ -6858,3 +6858,16 @@ Charlie    21 may 2005
         postupgrade
         PostInstall.cpp
 
+David  21 May 2005
+    - API: there seem to be problems with the user of timer signals
+        in the BOINC API (Unix version).
+        On some platforms the signals are delivered to both
+        the worker and graphics thread,
+        and they can deadlock on something down in _vprintf().
+
+        Rather than try to sort this out,
+        we'll switch to using a separate thread instead of signals.
+        (from J.R. Oldroyd)
+
+    api/
+        boinc_api.C
diff --git a/doc/download.php b/doc/download.php
index 907e090d03..bddbf65aef 100755
--- a/doc/download.php
+++ b/doc/download.php
@@ -21,7 +21,7 @@ function show_detail($v) {
     $path = "dl/$file";
     $url = "http://boinc.berkeley.edu/$path";
     $dlink = "<a href=$url>$file</a>";
-    $md = md5_file($path);
+    //$md = md5_file($path);
     $s = number_format(filesize($path)/1000000, 2);
     $date = $v["date"];
     $type = $v["type"];
@@ -33,7 +33,7 @@ function show_detail($v) {
     dl_item("Version number", $num);
     dl_item("Release date", $date);
     dl_item("Installer type", $type);
-    dl_item("MD5 checksum of download file", $md);
+    //dl_item("MD5 checksum of download file", $md);
     if ($features) {
         dl_item ("New features", $features);
     }
@@ -66,7 +66,7 @@ function show_version_xml($v, $long_name) {
     $path = "dl/$file";
     $url = "http://boinc.berkeley.edu/$path";
     $dlink = "<a href=$url>$file</a>";
-    $md = md5_file($path);
+    //$md = md5_file($path);
     $s = number_format(filesize($path)/1000000, 2);
     $date = $v["date"];
     $type = $v["type"];
@@ -83,12 +83,12 @@ function show_version_xml($v, $long_name) {
     <url>$url</url>
     <filename>$file</filename>
     <size_mb>$s</size_mb>
-    <md5>$md</md5>
     <installer>$type</installer>
     <features>$features</features>
     <issues>$bugs</issues>
 </version>
 ";
+//    <md5>$md</md5>
 }
 
 function show_version($pname, $i, $v) {