[Simh] KS10 IMP documentation

[Phil Budne]

ISTR the AN22 IMP interface for the KS10 was only ever used in pre-TCP
Internet (aka "NCP") days (would that be TOPS-20 v3?). I doubt *THAT*
it what you're looking for (even if it's available), but the "IMP" has
been simulated in SIMH, so there would be something for it to talk to!

ISTR ITS running on KS10's used third party (ACC?) interfaces for
sending IP packets to IMPs.  When the IMP (connections?) went away,
the ITS KS10's were only accessible via CHAOSnet (the real thing,
using CH11 interfaces, not CHAOS over ethernet).

A bit of work was done at MIT for a third-party (Interlan?) Unibus
Ethernet for the KS10 ITS machines, but with the 14-byte Ethernet
header not being a multiple of four (the number of 8-bit bytes packed
into a 36-bit word), 32-bit TCP header fields were split across 36-bit
words, which drained _my_ enthusiasm for making a go at it!

Also on the NCP front, there is vestigial NCP code in ITS, but from
the era when AI/ML/DM were KA's and MC was a KL.  ISTR the MC
interface was home built part of a cabinet marked "KL-UDGE"??

p