[HECnet] Multinet alternatives ...

[Thomas DeBellis]

Not much, regretfully.  Tops-20 was first brought up on a KI processor 
as a port from BBN TENEX which used a considerably more sophisticated 
page box.  I don't believe it was ever productized and these sources are 
believed lost.

By and large, a KI used some different hardware than a KL (the RH20 
comes to mind) although they could and did share a great deal of equipment.

You would likely have never seen a DTE on a KS processor; there was no 
need and no PDP-11 processor.  The KS addressed the Unibus directly.  A 
DTE was found on PDP-11's (I think 11/34's and 11/40's) to connect them 
to KL-10's.  One side was unibus based and the other connected to the KL 
(I don't recall whether it was massbus based).  You could have 
theoretically used a DTE to connect a KS to a KL, but I don't believe 
this was ever done.

One assumes that SIMH could emulate the unibus side of the DTE interface 
for the PDP-11, perhaps encapsulating the packets and sending them to a 
KLH10 based DTE via IP datagrams.  You could bring up a nice bit of 
software, IBM HASP multileaving comes to mind and perhaps an AN20.

Although he really loved it, MRC had a lot of comments about the KL.  It 
is a difficult beast to emulate; the page box is far more complex than 
the KI (although by no means as complex as the BBN page box).  There are 
meters and a bunch of other things.  The KL-B class extended addressing 
complicates things too.

On 2/26/20 4:01 PM, Ray Jewhurst wrote:
> KL simulation for Simh is on its way by Rich Cornwall and at last 
> check it's only a few months out. He already has a KI simulator but I 
> am not sure what that will do as far as TOPS20.
>
> Ray
>
> On Wed, Feb 26, 2020, 3:44 PM Robert Armstrong <bob at jfcl.com 
> <mailto:bob at jfcl.com>> wrote:
>
>     > Thomas DeBellis [tommytimesharing at gmail.com
>     <mailto:tommytimesharing at gmail.com>] wrote:
>     >Otherwise, personally, I think it would be a cool idea for SIMH
>     to have
>     >full support for DTE's ...
>
>       That's the problem - the KS never had DTEs, not even close, and
>     simh only emulates a KS10.  The only way out is to emulate a KL,
>     and that's a big job.  KLH10 already does that pretty well, and I
>     don't think simh will ever acquire KL emulation.
>
>       The other issue with the KS was that it was limited to two
>     sections (512KW) of memory, and that's pretty much a show stopper
>     for all later versions of TOPS20.
>
>       It runs TOPS10 fairly well, though.
>
>     Bob
>
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