On 2013-09-23 20:07, John Wilson wrote: From: Clem Cole <clemc at ccc.com> I think you are right, but my memory is fuzzy on all this now. IIRC with the MIT/BBN pager modification, KA10's could run ITS or TENEX (aka twinex - which was the Tops-20 pre-cursor ). I'm 99.99% sure the BBN and MIT pagers are unrelated, even though they were both built for the KA10 and around the same time. TOPS-20 and ITS paging are certainly different universes. I can add that additional 0.01% in that case. And TWENEX was just the joking name for TOPS-20 used by non-DEC people to hint at the heritage from TENEX that TOPS-20 had. KA10 could run ITS or TENEX. KA10 was never able to run TOPS-20. I know someone wrote some text about the KL pager microcode which went through some of these details, but I can't find that text right now. (I think it was the KL pager, but maybe it was the KS) Johnny