[HECnet] This is probably been asked already but....

[Johnny Billquist]

On 2012-07-02 20:06, Paul_Koning at Dell.com wrote:

On Jul 2, 2012, at 11:47 AM, Johnny Billquist wrote:

On 2012-07-02 16:40, Paul_Koning at Dell.com wrote:

On Jul 2, 2012, at 10:21 AM, Bob Armstrong wrote:

...
  RSX-11S was the "embedded system OS" of the PDP-11 world (at least as far
as DEC's offerings went).

That and RT-11.   And MicroPower-Pascal, of which I know nothing apart from its name.   Was that the RTOS used with the T-11 (the first single-chip PDP-11?)   I seem to remember that it was used as the RTOS in the LA-120 printer.   Having a real OS allowed it to do fancy stuff like bidirectional printing, the first DEC printer to do so.

I'm not sure how practical the other ones were as embedded systems. The big point with RSX-11S is that it's all just one binary for the whole system. There are no disks. In fact, you can't even have things on disk in the sense that you think for other systems.
Without disks, you could put this all on PROM, flash, or whatever. Or (which I think was more common), download from the net, and then run.

As far as I know, RT likes a disk, or something disklike, such as DECtape (real or even the fake "DECtape II").   But Micropower, I'm pretty sure, is a deep embedded system that runs from ROM/RAM.

I remember MicroPower Pascal, but never used it, or even saw it.
-11S is always diskless and memory resident, so it's easy.

-11S, -11M and -11M-PLUS all share the same sources, by the way. (At least as far as capabilities are shared - there are sources that are M+ only for instance.)

	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