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.
Oh, and I almost forgot - the only use of RT11 that I know of for an
"embedded" system was the CFEs for the VAX 780 and 8600 (on a 11/03 in the
former and a PRO in the latter). Are there any more?
Bob
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.
Did the LA120 have a T11 in it? Wow - makes me want to go take mine apart
and look :-)
It's good that you brought this up, because I was going to ask about
examples of devices that used embedded PDP-11s, probably mostly DEC made but
not always.
For example, the RFxx drives (all of 'em, I think) used a T11 and I'm
pretty sure ran some variant of RSX-11S.
The RQDXn controllers also used a T11, but I have no idea what firmware
was inside them.
The HSC controllers had PDP-11s in them, didn't they? I don't remember
which model but I bet the OS was another RSX derivative.
Some of the bigger DECserver terminal servers were PDP-11 based (not T11,
but an 11/53 for example). Don't know if the little ones (e.g.
DECserver-100, 200, etc) were T11 or 68K based. Actually if we go down that
path there were a number of PDP-11 and PDP-8 based front ends for the -10
that were essentially "terminal servers" (although we didn't call them as
such in those days) - the DC68/680I, DN20, etc. I actually worked on a
couple of those, and they had "ad hoc" software that didn't use any official
OS.
Bob
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.
paul
Bob Armstrong wrote:
One of the goals of 11M was to get something that could run on a really
small PDP-11 without an MMU, which 11M can.
M can run without an MMU?? RSX-11S can, but I don't think 11M can.
OK, 11S is just a stripped down 11M, but it was still a separate product.
Can you actually gen an unmapped system with a 11M distribution?
I have RSX-11M V4.0 RL01 kit, RSXM32 volume is an unmapped RSX-11M.
--
RSX-11M V4.0 BL32 28.K (BASELINE)
>RED DL:=SY:
>RED DL:=LB:
>MOU DL:RSXM32
>@DL:[1,2]STARTUP
>* PLEASE ENTER TIME AND DATE (HR:MN DD-MMM-YY) [S]:
--
SYSGEN asks if generated system should be unmapped, so probably you an generate it :)
On 2012-07-02 16:21, Bob Armstrong wrote:
One of the goals of 11M was to get something that could run on a really
small PDP-11 without an MMU, which 11M can.
M can run without an MMU?? RSX-11S can, but I don't think 11M can.
It can. It's called an "unmapped" system. That's when you really need to start playing with all those values after partition names... Both at the MCR level, and the TKB level.
OK, 11S is just a stripped down 11M, but it was still a separate product.
Can you actually gen an unmapped system with a 11M distribution?
Yes.
And -11S is stripped down rather seriously. There are no file systems in -11S. -11S is basically a memory only thing. (Perfect for net bootable systems, btw...)
Also, 11S could run without any kind of disk or mass storage (e.g. a
complete 11S image could be downloaded via MOP) but I don't think 11M ever
could.
Correct. In fact, -11S never have any file system. You can always have the disk devices, but they are without structure.
-11M is disk based, always. Mapped or unmapped.
RSX-11S was the "embedded system OS" of the PDP-11 world (at least as far
as DEC's offerings went).
Yep.
In an unrelated question - was RSX-20F (the CFE for the KL10) based on
11S? In ran on an unmapped 11/40, so I assume it must have been.
It's actually more or less an unmapped -11M. Same reason. No disks in -11S. RSX-20F is using the shared RP06 as storage.
Johnny
One of the goals of 11M was to get something that could run on a really
small PDP-11 without an MMU, which 11M can.
M can run without an MMU?? RSX-11S can, but I don't think 11M can.
OK, 11S is just a stripped down 11M, but it was still a separate product.
Can you actually gen an unmapped system with a 11M distribution?
Also, 11S could run without any kind of disk or mass storage (e.g. a
complete 11S image could be downloaded via MOP) but I don't think 11M ever
could.
RSX-11S was the "embedded system OS" of the PDP-11 world (at least as far
as DEC's offerings went).
In an unrelated question - was RSX-20F (the CFE for the KL10) based on
11S? In ran on an unmapped 11/40, so I assume it must have been.
Bob
On 2012-07-02 15:39, Paul_Koning at Dell.com wrote:
On Jul 1, 2012, at 9:02 PM, Steve Davidson wrote:
...
IAS-11 was based on RSX-11D.
I worked on that for my first job at DEC, supporting Typeset-11, which was a newspaper typesetting and advertisement management system. It was originally implemented as a turnkey product on top of RSX-11D, then ported to IAS. There was also a Typeset-8, which was created by the group right next to it and used some of the same terminals, but whether anything else carried over I don't know.
The relationship between those two was very obvious, especially since we turned off the timesharing piece and kept only the RSX compatible real time piece of IAS.
Curiously enough, it seems (I never got very close to it) that RSX-11M (and M+) were completely unrelated to -D apart from having a mostly common API (as we didn't call it yet). RSX-11D very clearly went back directly to RSX-15 -- I once saw a listing of RSX-15 lying around because it was supported very close to where I worked, and a glance at the first few pages showed lots of data structures identical in name, purpose, and layout to what the RSX-11D kernel used.
Paul, you're a wonderful source of information, as usual (both the previous post on DECnet history), and this...
To comment a tiny bit of what I know on RSX. RSX-11M was a clean reimplementation of RSX by Dave Cutler. Allegedly done in a rather short time, with the aim of much better utilization of resources.
As such, it did indeed implement more or less the same API, but the internals are all different. So user applications compile fine on either. The programs might even work fine without recompiling, but I don't know for sure.
Device drivers, and all stuff that knows anything about the kernel is rather different though.
One of the goals of 11M was to get something that could run on a really small PDP-11 without an MMU, which 11M can. (I seriously doubt that could ever be done with -11D.)
-11M+, which came later, was basically reimplementing some of the stuff in -11D, since -11M+ had as the target the large PDP-11 systems. Specifically the 11/70, as well as the never introduced 11/74. Which is why -11M+ also have a very capable online reconfiguration tool (that turned out to be useful in general, but it was specifically written for the 11/74).
So -11M+ requires even more hardware than -11D, but does things differently than -11D.
Johnny
Area: 20 (down for another day or two)
Location: Louisville, KY, USA
Router: WOPR:: -- connected via Multinet to 19, bridge to johnny
Joe
On Sun, Jul 1, 2012 at 4:16 PM, Fred <fcoffey at misernet.net> wrote:
Hi all:
My turn ... :)
Area: 33
Name: Fred Coffey
Location: Sandusky, Ohio (midwest, between Toledo and Cleveland)
Router: FRUGAL:: - connected via Multinet Tunnels to area 2 and 19
Cheers,
Fred
On Jul 1, 2012, at 9:02 PM, Steve Davidson wrote:
...
IAS-11 was based on RSX-11D.
I worked on that for my first job at DEC, supporting Typeset-11, which was a newspaper typesetting and advertisement management system. It was originally implemented as a turnkey product on top of RSX-11D, then ported to IAS. There was also a Typeset-8, which was created by the group right next to it and used some of the same terminals, but whether anything else carried over I don't know.
The relationship between those two was very obvious, especially since we turned off the timesharing piece and kept only the RSX compatible real time piece of IAS.
Curiously enough, it seems (I never got very close to it) that RSX-11M (and M+) were completely unrelated to -D apart from having a mostly common API (as we didn't call it yet). RSX-11D very clearly went back directly to RSX-15 -- I once saw a listing of RSX-15 lying around because it was supported very close to where I worked, and a glance at the first few pages showed lots of data structures identical in name, purpose, and layout to what the RSX-11D kernel used.
paul
On Jul 1, 2012, at 9:33 PM, Johnny Billquist wrote:
On 2012-07-02 03:17, Gregg Levine wrote:
On Sun, Jul 1, 2012 at 9:10 PM, Bob Armstrong <bob at jfcl.com> wrote:
...
What I am curious about is how the PDP-11s talked to DEC Net based systems.
And which ones of the R* operating systems could be confused into
doing that, and in what ways.
Well, considering the fact that DECnet was born on the PDP-11, the question should perhaps be rephrased as how non-PDP11 systems managed to talk on DECnet. :-)
If the question is more on a practical note of how connections were done, I think the original was over serial lines, but I might be wrong. Multidrop as well as some high speed links were available in Phase III, but ethernet only became an option with DECnet phase IV.
Not sure about the time frame for packet switched interfaces. They certainly existed in Phase IV, but I don't know if they were available already in phase III.
Let's see. Some history, as best as I remember it. This is partially before my time, and also partially derived from on-line history files...
DECnet Phase I was implemented on RSX. Not sure which flavor. I'd guess RSX11-M just because that's where the action was. DDCMP only, in software only as far as I recall. Probably on a DU-11.
DECnet Phase II was the first multi-platform DECnet. I suspect it's also the first that had formal hardware-independent protocol specifications. Protocols were DDCMP for the data links (point to point only, sync or async), NCP, and DAP. Also around that time some other things appeared; I think MAIL-11 (email). I'm fairly sure that predates DECnet Phase III because I vaguely remember it using UUCP style paths (foo::bar::pkoning) in that time -- which later came back for PMR support. Supported operating systems included RSX, RSTS, VMS, TOPS-10, and I think TOPS-20. Terminal emulation appeared, but in an OS-specific fashion that was basically undocumented. Network management (NCP and NML) was now part of the standard architecture and fairly consistent among the various implementations.
DECnet Phase III introduced routing, which made it useable for networks the size of the DEC internal network ("Engineering network" or E-net for short) by introducing routing: one area, 255 nodes max. Still no Ethernet, but this is when multipoint DDCMP was added. That was a bit of a dancing bear ("The amazing thing is not how well the bear dances, but that it dances at all") in my view, but it did work after a fashion. It may be that packet switching (X.25) appeared here -- I never knew much about that since it wasn't ever considered for RSTS and was essentially nonexistent in the USA as far as I could tell. Check the Phase III routing layer spec ("version 1.3") and/or the Phase III network management layer spec -- if either can be found it will certainly answer this question.
DECnet phase IV adds areas, and increases the bottom level routing to 1023 nodes max by creating a way to break up the routing message into pieces (and send only what changed, as opposed to the data for the whole network every time as Phase III did). And, most importantly, it adds Ethernet. The Ethernet packet formats are strangely different in the routing layer; this is a leftover from an earlier proposal for "Phase IV" which was intended to introduce long addresses and link-state routing; that was rejected by the implementers as being too hard and "Phase III Extended" was whipped up instead by a slight tweak of Phase III to make it hierarchical. Parts of the original "Phase IV" eventually ended up in Phase V, though not the addressing; that was replaced by OSI addressing. But things like the "lollypop sequence numbering" in the Phase V routing protocol (and in IS-IS, which came directly from there) carried over from the earlier proposal. BTW, note that OSPF was derived from DECnet Phase V routing, though the OSPF creators never bothered to give any credit for that. Supported platforms: eventually nearly all of the Phase III platforms, though some (like RSTS) took quite a while to get there.
BTW, high speed links -- by the standards of the time -- appeared around Phase II when the DMC-11 was introduced. It came in two flavors, one to support lines with modem control at up to 56 kb/s (actually, I suspect they would run somewhat faster, if you could find a modem to run faster) and the other for service within a building, running over coax at 1 Mb/s. By the standards of the late 1970s that was seriously fast, especially for PDP11 based minicomputers. It also was a strain for the microcontroller in the DMC-11, which is why that one speaks a somewhat buggy version of DDCMP. I may still have the details somewhere; it wasn't all that hard to make a standards-compliant DDCMP implementation work with a DMC-11 but it takes a few hacks here and there.
paul
