diff --git a/build/dump-diff.sh b/build/dump-diff.sh
new file mode 100644
index 00000000..de1c99ff
--- /dev/null
+++ b/build/dump-diff.sh
@@ -0,0 +1,86 @@
+#!/bin/sh
+
+cleanup() {
+    cd "$home"
+    rm -rf "$tmp"
+}
+
+absolute() {
+    case "$1" in
+        /*) echo "$1";;
+        *) echo "$PWD/$1";;
+    esac
+}
+
+tape1="`absolute $1`"
+tape2="`absolute $2`"
+home="$PWD"
+tmp="$PWD/tmp.$$"
+
+trap cleanup EXIT INT TERM QUIT
+
+mkdir "$tmp"
+cd "$tmp"
+
+mkdir tape1
+cd tape1
+itstar xf "$tape1"
+rm -- */_file_.\(dir\) */m_f_d_.\(file\)
+cd "$tmp"
+mkdir tape2
+cd tape2
+itstar xf "$tape2"
+rm -- */_file_.\(dir\) */m_f_d_.\(file\)
+cd "$tmp"
+rm "$home/diffs"
+
+output() {
+    echo "$1: $2"
+    echo "$2" >> "$home/diffs"
+}
+
+diff_file() {
+    file="$1"
+    if test -L "$file"; then
+        if test -L "../tape1/$file"; then
+            l1=`readlink "../tape1/$file"`
+            l2=`readlink "$file"`
+            if test "$l1" \!= "$l2"; then
+                output "UPDATED LINK" "$file"
+            fi
+        else
+            output "NEW LINK" "$file"
+        fi
+    elif test -f "../tape1/$file"; then
+        if cmp -- "$file" "../tape1/$file" > /dev/null; then
+            :
+        else
+            dis10 "$file" 2> /dev/null | grep -v -e 'Creation time:' -e 'Symbol ' -e '^[0-7][0-7][0-7]   [0-7]' > "$tmp/TMP1"
+            dis10 "../tape1/$file" 2> /dev/null | grep -v -e 'Creation time:' -e 'Symbol ' -e '^[0-7][0-7][0-7]   [0-7]' > "$tmp/TMP2"
+            if cmp -- "$tmp/TMP1" "$tmp/TMP2" > /dev/null; then
+                :
+            else
+                output "UPDATED FILE" "$file"
+            fi
+        fi
+    else
+        output "NEW FILE" "$file"
+    fi
+}
+
+cd tape2
+for dir in *; do
+    if test -d "../tape1/$dir"; then
+        for file in $dir/*; do
+            test -r "$file" && diff_file "$file"
+        done
+    else
+        output "NEW DIRECTORY" "$dir"
+    fi
+done
+
+cd "$tmp/tape2"
+head -1 "$home/diffs" | xargs itstar cvf "$home/diffs.tap"
+tail +2 "$home/diffs" | xargs itstar rvf "$home/diffs.tap"
+cd "$home"
+rm "$home/diffs"