[HECnet] Another TOPS-10 DECnet problem

[Johnny Billquist]

On 2021-11-12 21:01, Paul Koning wrote:
> 
> 
>> On Nov 11, 2021, at 6:49 PM, Johnny Billquist <bqt at softjar.se> wrote:
>>
>> RSX-11M-PLUS can have up to 256 terminals. However, I sortof doubt much useful stuff would happen if you had that many users running interactively.
>>
>> I think it was more used for systems where you had some clever programs running that controlled lots of terminals.
> 
> RSTS has an API for that, allowing one program to control lots of terminals without having to open lots of individual files for each terminal.  It makes it possible to support 127 terminals, even though the number of logged-in users is limited to 63.

There is no hard limit on the number of logged in users in RSX. And no 
hard limit on the number of running tasks either.

Controlling lots of terminals from one process in RSX is easy. You do 
need to have the terminals open, but the limit on devices accessed from 
one task is 256. You don't need to have active I/Os to any terminal in 
order to read from them, so it's actually very little resources 
required. A little bit of memory, but that's it.

I believe this was used out by customers in lots of places. I never saw 
any really big ones, but I heard about 911 dispatch centers in the US. 
But small scale solutions on the same principles were/are being run that 
I know of...

   Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol