[HECnet] Another TOPS-10 DECnet problem

[Johnny Billquist]

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.

But PDP-11 systems were/are pretty capable, considering some of the 
limitations... And they are still being used in some places, which I 
find pretty nice. And of course, I continue whack at them when I get a 
chance. The combination of TCP/IP, web servers, and stuff like 
Datatrieve makes it look almost like some modern stack of tools. I'm 
having blast nearly every day. I just wish I could locate the sources of 
the layered products...

MRC vs. BAH was sometimes interesting. I usually did side with MRC in 
those discussions, but I tried to mostly keep out of it, since PDP-10 
isn't my forte. But it was often somewhat interesting to read and 
follow, I thought. MRC never quit standing up for TOPS-20. :-)

   Johnny


On 2021-11-12 00:38, Thomas DeBellis wrote:
> Believe me, a large number of us in the systems group were really sorry 
> to retire our 11/60 (or 11/50? 55?) RSTS system.  We just thought it was 
> so neat.  And we missed it for years.  The assembler was a little 
> strange for us, but definitely easier for us to hack than PDP-8 (which 
> had its own advocates) or IBM 370 (which had truly maniacal devotees)  
> The architecture had some very interesting ideas.
> 
> I was also one of the few that would move between DEC and IBM, which is 
> quite a paradigm shift if you've ever had to stare a 3270 in the face 
> after EMACS.
> 
> My students always seem to ask me which OS I prefer or what language is 
> the best, my response is always the same, "I like the OS that I get paid 
> to use and the language I get paid to program in".  One has to earn a 
> living...
> 
> I honestly don't know where those two got their stamina from...
> 
> ------------------------------------------------------------------------
> On 11/11/21 6:26 PM, Johnny Billquist wrote:
>> And where I'm from we were regularly running 40 people on one 11/70 
>> with RSTS/E, and on bad days we were above 60. But then it was 
>> miserably slow...
>>
>> And yes, I have plenty of memories of the mails between MRC and BAH. :-)
>>
>>   Johnny
>>
>> On 2021-11-11 23:48, Thomas DeBellis wrote:
>>> Oh, that old cat fight?  Meow!!  I'm walking away from it; I don't 
>>> know how much email got spewed between MRC and BAH about it.  I don't 
>>> think either side ever got the point that you are not comparing 
>>> apples to apples.
>>>
>>> Having looked at both schedulers, I don't immediately see that either 
>>> was more efficient than the other.  There clearly was cross 
>>> fertilization in a number of areas.
>>>
>>> Recall that Tops-20 has processes and that a job may have a large 
>>> number of processes.  The number of jobs then is not going to be a 
>>> valid comparison.  For example, let's take a look at Galaxy on 
>>> Tops-10, which occupies 10 job slots:
>>>
>>> Job    Who     Line#    What Size(P) State   Run Time
>>>
>>>  1    [OPR]     DET     NEBULA  26+40   HB 0
>>>  3    [OPR]      0      QUEUE   9+38    ^C 1
>>>       [OPR]     DET     QUASAR  40+40   SL 1
>>>  9    [OPR]     DET     PULSAR  5+40    HB SW 0
>>> 10    [OPR]     DET     ORION   109+40  SL 0
>>> 11    [OPR]     DET     NML     15+18   HB 3
>>> 13    [OPR]     DET     CDRIVE  30+40   HB 0
>>> 14    [OPR]     DET     FAL-10  104+40  SL 1
>>>
>>>
>>> They're all underneath a _single_ job on Tops-20 or built into the 
>>> EXEÇ, but producing the same load because it is the same code.
>>>
>>> We did do some instrumenting and we found that the snazzy parsing 
>>> (COMND%) was not contributing that much to load.  There was some 
>>> overhead simulating UUO's, which are obviously natively executing on 
>>> Tops-10.  Nearly all editing was done with WYSIWYG video editing, 
>>> which surely must produce more load than TECO or SOS.  Some work was 
>>> put into TEXTI% to mitigate the context switching.
>>>
>>> MRC's position was that Tops-20 was doing more, but I'm not sure how 
>>> comfortable I am with that.  Having used and programmed both, I think 
>>> it's more like 'doing differently'.  I would say that it was rare to 
>>> find people who could easily move between the two and/or who weren't 
>>> highly opinionated.
>>>
>>> It's a waste of time; you bought what did the job best for your 
>>> environment.  It's kind of like apples and pineapples; they sound the 
>>> same but they're just not.
>>> ------------------------------------------------------------------------
>>> On 11/11/21 5:20 PM, Robert Armstrong wrote:
>>>>
>>>> >You had a 20 that would handle 600 students in 1977/???/
>>>>
>>>>   I think he said something about six 20s…  I’m pretty sure there’s 
>>>> no way one CPU would have handled 600 timesharing users.   We could 
>>>> get to around 120 on a single KL10E with TOPS-10 before it got 
>>>> unbearably slow.  With TOPS-20 on the same hardware we could only 
>>>> get to 80 or so; TOPS20 was something of a pig.
>>>>
>>>> Bob
>>>>
>>

-- 
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