16 Jul
2019
16 Jul
'19
7:08 p.m.
On 2019-07-16 17:50, John Forecast wrote:
Ah, yes, I tend to skim over the mP changes, but you are right. DECnet
is one of those things that got hit because of that, as well as some
kernel parts. It's still fairly contained. It's just that CEX knows a
little too much to not get affected. Most device drivers are totally
unaware of mP aspects.
Interesting that you think you might have improved DECnet with a bit
more work. As it stands, it works fine today. But I haven't looked into
how much might be running without cache enabled. But I am running a
simulated 11/74. That is Mim.Update.UU.SE. You can both browse to it,
and telnet to it. Usually I only have two CPUs online, since there are
still some issues with the emulation. But otherwise it works fine.
I also had to figure out some issues with TCP/IP and multiprocessor
support. That was interesting. :-)
No. Last/latest release was in 1998/1999 (depends on whether you look at 11M or 11M+).
But it was still all just phase IV.
That must be a Mentec release? I was long gone from DEC at that point in time.
Yes. Mentec released both 4.5 and 4.6 of M+. The last DEC release was
V4.4, in 1993 or 1994. Right before it was sold off to Mentec.
(Corresponding 11M was 4.7 and 4.8, with the last DEC release being 4.6.)
The M+ 4.6 disk image at trailing-edge actually contains the DECnet code
as well. And yes, DECnet-11M-PLUS V4.5 and V4.6 was released in parallel
with RSX-11M-PLUS V4.5 and V4.6.
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
On Jul 15, 2019, at 7:48 PM, Johnny Billquist
<bqt at softjar.se> wrote:
On 2019-07-15 17:36, John Forecast wrote:
Right. And I/O completion is normally handled by a couple of routines in the kernel, so
the driver itself can be pretty minimal.
There were a lot of small changes throughout the networking code to get it running
on our dual-processor. We eventually shipped with the kernel networking code running with
cache bypass enabled and the intention of revisiting it in a later release. One the 11/74
was cancelled, we were never given the opportunity? On Jul
14, 2019, at 11:55 PM, Thomas DeBellis <tommytimesharing at gmail.com
<mailto:tommytimesharing at gmail.com>> wrote:
2. RSX-11M/11S - any PDP-11 system with sufficient memory + devices
Device drivers ran as part of the ?kernel? serialized by the fork block mechanism I guess RSX-11M+ could be consider a separate
class adding I/D space, supervisor mode and multi-processor support.
Nah. 11M+ is really very similar to 11M. They pretty much share the same codebase, but M+
extends some data structures with a bit more information, and also adds a couple of more
structures to make the system more flexible.
The splitting of I/D space, as well as supervisor mode actually have very little impact
on the kernel. There is obviously a bit more work at a context switch, and there are a
couple of details around ASTs, which can switch between user and supervisor, but much of
the rest don't know or care. And drivers can pretty much be moved straight over,
although you normally would want to modify them to take advantage of some nifty additional
capabilities provided by M+.
1. What is the
latest Phase DECnet that 11M will run? I guess the
last release was 93?
Phase IV. The last release I see on bitsavers.org
<http://bitsaver.org> was 4.5 in Oct 1989 Latest 11M is
V4.8, and latest 11M+ is V4.6.
I think they are even available to trailing-edge?
That?s the base 11M/11M+ distribution? Do you know if there was a corresponding
DECnet release?