diff --git a/checkin_notes b/checkin_notes
index 981444b526..b40077140e 100644
--- a/checkin_notes
+++ b/checkin_notes
@@ -2534,3 +2534,9 @@ David  10 Mar 2012
         vda_lib.cpp,h
         ssim.cpp
         vdad.cpp
+
+David  10 Mar 2012
+    - forgot to add files
+
+    vda/
+        stats.cpp,h (new)
diff --git a/vda/stats.cpp b/vda/stats.cpp
new file mode 100644
index 0000000000..7da23649f5
--- /dev/null
+++ b/vda/stats.cpp
@@ -0,0 +1,143 @@
+// This file is part of BOINC.
+// http://boinc.berkeley.edu
+// Copyright (C) 2012 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/>.
+
+#include <string.h>
+#include <stdio.h>
+#include <limits.h>
+
+#include "stats.h"
+
+//#define SAMPLE_DEBUG
+
+char* time_str(double t) {
+    static char buf[256];
+    int n = (int)t;
+    int nsec = n % 60;
+    n /= 60;
+    int nmin = n % 60;
+    n /= 60;
+    int nhour = n % 24;
+    n /= 24;
+    sprintf(buf, "%4d days %02d:%02d:%02d", n, nhour, nmin, nsec);
+    return buf;
+}
+
+void STATS_ITEM::init(const char* n, const char* filename, STATS_KIND k) {
+    f = fopen(filename, "w");
+    strcpy(name, n);
+    kind = k;
+    value = 0;
+    integral = 0;
+    switch (kind) {
+    case DISK:
+    case NETWORK:
+        extreme_val = 0;
+        break;
+    case FAULT_TOLERANCE:
+        extreme_val = INT_MAX;
+        break;
+    }
+    extreme_val_time = 0;
+    first = true;
+}
+
+void STATS_ITEM::sample(double v, bool collecting_stats, double now) {
+#ifdef SAMPLE_DEBUG
+    switch (kind) {
+    case DISK:
+        printf("%s: %s: %fGB -> %fGB\n", now_str(), name, value/1e9, v/1e9);
+        break;
+    case NETWORK:
+        printf("%s: %s: %fMbps -> %fMbps\n", now_str(), name, value/1e6, v/1e6);
+        break;
+    case FAULT_TOLERANCE:
+        printf("%s: %s: %.0f -> %.0f\n", now_str(), name, value, v);
+        break;
+    }
+#endif
+    double old_val = value;
+    value = v;
+    if (!collecting_stats) return;
+    if (first) {
+        first = false;
+        prev_t = now;
+        return;
+    }
+    double dt = now - prev_t;
+    prev_t = now;
+    integral += dt*old_val;
+    switch (kind) {
+    case DISK:
+    case NETWORK:
+        if (v > extreme_val) {
+            extreme_val = v;
+            extreme_val_time = now;
+        }
+        break;
+    case FAULT_TOLERANCE:
+        if (v < extreme_val) {
+            extreme_val = v;
+            extreme_val_time = now;
+        }
+        break;
+    }
+
+    fprintf(f, "%f %f\n", now, old_val);
+    fprintf(f, "%f %f\n", now, v);
+}
+
+void STATS_ITEM::sample_inc(double inc, bool collecting_stats, double now) {
+    sample(value+inc, collecting_stats, now);
+}
+
+void STATS_ITEM::print(double now) {
+    sample_inc(0, true, now);
+    double dt = now - start_time;
+    switch (kind) {
+    case DISK:
+        printf("    mean: %fGB.  Max: %fGB at %s\n",
+            (integral/dt)/1e9, extreme_val/1e9, time_str(extreme_val_time)
+        );
+        break;
+    case NETWORK:
+        printf("    mean: %fMbps.  Max: %fMbps at %s\n",
+            (integral/dt)/1e6, extreme_val/1e6, time_str(extreme_val_time)
+        );
+        break;
+    case FAULT_TOLERANCE:
+        printf("    mean: %.2f.  Min: %.0f at %s\n",
+            integral/dt, extreme_val, time_str(extreme_val_time)
+        );
+        break;
+    }
+}
+
+void STATS_ITEM::print_summary(FILE* fout, double now) {
+    double dt = now - start_time;
+    switch (kind) {
+    case DISK:
+        fprintf(fout, "%f\n", integral/dt);
+        break;
+    case NETWORK:
+        fprintf(fout, "%f\n", integral/dt);
+        break;
+    case FAULT_TOLERANCE:
+        fprintf(fout, "%f\n", extreme_val);
+        break;
+    }
+}
+
diff --git a/vda/stats.h b/vda/stats.h
new file mode 100644
index 0000000000..5794d8df67
--- /dev/null
+++ b/vda/stats.h
@@ -0,0 +1,43 @@
+// This file is part of BOINC.
+// http://boinc.berkeley.edu
+// Copyright (C) 2012 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/>.
+
+// keeps track of a time-varying property of a file
+// (server disk usage, up/download rate, fault tolerance level)
+//
+
+typedef enum {DISK, NETWORK, FAULT_TOLERANCE} STATS_KIND;
+
+struct STATS_ITEM {
+    STATS_KIND kind;
+    double value;
+    double integral;
+    double extreme_val;
+    double extreme_val_time;
+    double prev_t;
+    double start_time;
+    bool first;
+    char name[256];
+    FILE* f;
+
+    void init(const char* n, const char* filename, STATS_KIND k);
+    void sample(double v, bool collecting_stats, double now);
+    void sample_inc(double inc, bool collecting_stats, double now);
+    void print(double now);
+    void print_summary(FILE* f, double now);
+};
+
+extern char* time_str(double);