PDP 8 Timesharing

Johnny Billquist bqt at update.uu.se
Mon Nov 30 14:49:06 CST 2015

On 2015-11-30 21:34, Jay West wrote:
> Johnny wrote...
> ------------------------------------
> Fun stuff. However, I do not expect you'll see much impovement in performance in ETOS compared to MULTOS.
> You'll gain if you have code that do CIF n, followed by much code before the JMP/JMS, but that is not exactly a common pattern in most PDP-8 code.
> Also, MULTOS do some clever stuff. It actually will modify in memory code that do polled loops for example, to not do those. Unless ETOS do the same, that might actually hurt ETOS more. Also, MULTOS is the only timesharing system I know that actually also handles the TD8E controller, if you happen to have one of those.
> I only wish I knew where I have version 2 of MULTOS. I uploaded version
> 1 a long time ago, but only at a later date realized that it wasn't the latest version. I *think* I should have version 2 somewhere as well, but my memory might be wrong also.
> -------------------------------------
> I would love to see some comparison between ETOS and MULTOS by anyone "in the know". I'd just like a nice timeshareing system for my 8E that is close to OS/8 and runnable with the hardware I have.

Well, if you have a 8E with a clock, and you run OS/8, then you can run 
MULTOS. Then you need (of course) serial lines...

MULTOS is like running OS/8, and most of the time you'll not even notice 
the difference, except you have to log in, and you might notice the 
"strange" device name on your system. Pretty much all OS/8 software runs 
just fine under MULTOS, and most of the time at about the same speed. Of 
course, it do depend on system load. But most systems are sitting idle 
most of the time anyway... :-)

Programs that do direct I/O to strange devices will not work, though. 
Nor will general interrupt-driven code. FRTS do work, however.
And you can write programs that use MULTOS specific features.

> Alternatively, TSS looks nice, but I am not sure that the full OS was ever found and is available? Hardware Reqs?

TSS8 is a different beast. It's not related to OS/8, so you'll have to 
adopt to a different environment, and each job only have 4K to play in.
And, as others mentioned, not sure if it works on an RK8E.


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

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