diff --git a/checkin_notes b/checkin_notes
index 688d4aaeea..6de136f88f 100755
--- a/checkin_notes
+++ b/checkin_notes
@@ -11558,3 +11558,14 @@ Bruce 9 Sept 2005
 Rom    9 Sept 2005 (staging)
     - Tag for 5.1.3 release, all platforms
       boinc_core_release_5_1_3
+
+David  9 Sept 2005
+    - fix web bug, make zip code optional
+    - add some comments
+
+    client/
+        client_state.C
+    html/user/
+        account_finish_action.php
+    lib/
+        util.C
diff --git a/client/client_state.C b/client/client_state.C
index 2beb6280b2..69fe4f456c 100644
--- a/client/client_state.C
+++ b/client/client_state.C
@@ -402,8 +402,15 @@ void CLIENT_STATE::do_io_or_sleep(double x) {
             &tv
         );
         //printf("select in %d out %d\n", all_fds.max_fd, n);
+
+        // Note: curl apparently likes to have curl_multi_perform()
+        // (called from net_xfers->got_select())
+        // called pretty often, even if no descriptors are enabled.
+        // So do the "if (n==0) break" AFTER the got_selects().
+
         net_xfers->got_select(all_fds, x);
         gui_rpcs.got_select(all_fds);
+
         if (n==0) break;
 
         now = dtime();
diff --git a/doc/credit.php b/doc/credit.php
index 2eda2df7ce..dfe54362a7 100644
--- a/doc/credit.php
+++ b/doc/credit.php
@@ -71,6 +71,7 @@ the following function is used to update the
 recent average credit of the host, user and team:
 <pre>",htmlspecialchars("
 
+
 void update_average(
     double work_start_time,       // when new work was started
                                     // (or zero if no new work)
@@ -82,6 +83,24 @@ void update_average(
     double now = dtime();
 
     if (avg_time) {
+        // If an average R already exists, imagine that the new work was done
+        // entirely between avg_time and now.
+        // That gives a rate R'.
+        // Replace R with a weighted average of R and R',
+        // weighted so that we get the right half-life if R' == 0.
+        //
+        // But this blows up if avg_time == now; you get 0*(1/0)
+        // So consider the limit as diff->0,
+        // using the first-order Taylor expansion of
+        // exp(x)=1+x+O(x^2).
+        // So to the lowest order in diff:
+        // weight = 1 - diff ln(2) / half_life
+        // so one has
+        // avg += (1-weight)*(work/diff_days)
+        // avg += [diff*ln(2)/half_life] * (work*SECONDS_PER_DAY/diff)
+        // notice that diff cancels out, leaving
+        // avg += [ln(2)/half_life] * work*SECONDS_PER_DAY
+
         double diff, diff_days, weight;
 
         diff = now - avg_time;
@@ -93,18 +112,18 @@ void update_average(
         avg *= weight;
 
         if ((1.0-weight) > 1.e-6) {
-	    avg += (1-weight)*(work/diff_days);
-        }
-        else {
+            avg += (1-weight)*(work/diff_days);
+        } else {
             avg += M_LN2*work*SECONDS_PER_DAY/half_life;
-	}
+        }
     } else if (work) {
+        // If first time, average is just work/duration
+        //
         double dd = (now - work_start_time)/SECONDS_PER_DAY;
         avg = work/dd;
     }
     avg_time = now;
 }
-
 "),"
 </pre>
 
diff --git a/html/user/account_finish_action.php b/html/user/account_finish_action.php
index 0e09032789..558755715b 100644
--- a/html/user/account_finish_action.php
+++ b/html/user/account_finish_action.php
@@ -30,7 +30,7 @@ if (!is_valid_country($country)) {
     show_error( "bad country");
 }
 
-$postal_code = strip_tags(process_user_text(post_str("postal_code")));
+$postal_code = strip_tags(process_user_text(post_str("postal_code", true)));
 
 $query = "update user set name='$name', country='$country', postal_code='$postal_code' where authenticator='$auth'";
 $retval = mysql_query($query);
diff --git a/lib/util.C b/lib/util.C
index b740210498..58684c8c85 100755
--- a/lib/util.C
+++ b/lib/util.C
@@ -792,18 +792,6 @@ int boinc_calling_thread_cpu_time(double &cpu_t) {
 // NOTE: if you change this, also change update_average in
 // html/inc/credit.inc
 //
-
-// David, the quick fix I have done is minimalist.  Consider the limit
-// as diff->0, using the first-order Taylor expansion of
-// exp(x)=1+x+O(x^2).
-// So to the lowest order in diff:
-// weight = 1 - diff ln(2) / half_life
-// so one has
-// avg += (1-weight)*(work/diff_days)
-// avg += [diff*ln(2)/half_life] * (work*SECONDS_PER_DAY/diff)
-// notice that diff cancels out, leaving
-// avg += [ln(2)/half_life] * work*SECONDS_PER_DAY
-
 void update_average(
     double work_start_time,       // when new work was started
                                     // (or zero if no new work)
@@ -815,6 +803,24 @@ void update_average(
     double now = dtime();
 
     if (avg_time) {
+        // If an average R already exists, imagine that the new work was done
+        // entirely between avg_time and now.
+        // That gives a rate R'.
+        // Replace R with a weighted average of R and R',
+        // weighted so that we get the right half-life if R' == 0.
+        //
+        // But this blows up if avg_time == now; you get 0*(1/0)
+        // So consider the limit as diff->0,
+        // using the first-order Taylor expansion of
+        // exp(x)=1+x+O(x^2).
+        // So to the lowest order in diff:
+        // weight = 1 - diff ln(2) / half_life
+        // so one has
+        // avg += (1-weight)*(work/diff_days)
+        // avg += [diff*ln(2)/half_life] * (work*SECONDS_PER_DAY/diff)
+        // notice that diff cancels out, leaving
+        // avg += [ln(2)/half_life] * work*SECONDS_PER_DAY
+
         double diff, diff_days, weight;
 
         diff = now - avg_time;
@@ -826,12 +832,13 @@ void update_average(
         avg *= weight;
 
         if ((1.0-weight) > 1.e-6) {
-	    avg += (1-weight)*(work/diff_days);
-        }
-        else {
+            avg += (1-weight)*(work/diff_days);
+        } else {
             avg += M_LN2*work*SECONDS_PER_DAY/half_life;
-	}
+        }
     } else if (work) {
+        // If first time, average is just work/duration
+        //
         double dd = (now - work_start_time)/SECONDS_PER_DAY;
         avg = work/dd;
     }