diff --git a/RUNSON b/RUNSON
new file mode 100644
index 000000000..c8b426c4b
--- /dev/null
+++ b/RUNSON
@@ -0,0 +1,15 @@
+Systems that sudo 1.3.1 is known to run on.
+
+ Op. System	CPU	Compilers	Patch	Reported	Special
+Name	Rev	Arch	Used		Level	By		Options
+=======	=======	=======	===============	======= =============== ===============
+SunOS	4.1	sun3	cc		5b1	todd miller	none
+SunOS	4.1.3	sun4	gcc2.6.3	5b1	todd miller	none
+HP-UX	9.05	hp700	gcc2.6.3	5b1	todd miller	none
+HP-UX	9.05	hp700	unbundled cc	5b1	todd miller	none
+IRIX	4.05H	mips	unbundled cc	5b1	todd miller	none
+IRIX	5.1.1.2	mips	unbundled cc	5b1	todd miller	none
+IRIX	5.1.1.2	mips	gcc2.6.3	5b1	todd miller	none
+NEXTSTEP 2.1	m68k	cc		5b1	todd miller	none
+NEXTSTEP 3.2	m68k	cc		5b1	todd miller	none
+DEC UNIX 3.0	alpha	cc		5b1	todd miller	none