11 Aug
2022
11 Aug
'22
12:04 p.m.
Message: 4
Date: Wed, 10 Aug 2022 12:29:24 +0200
From: Holger Veit <hveit01(a)web.de>
Subject: [TUHS] PCS Munix kernel source
Hi all,
I have uploaded the kernel source of 32 bit PCS MUNIX 1.2 to
https://github.com/hveit01/pcs-munix.
Thank you for sharing this work, most impressive!
MUNIX was an AT&T SVR3.x implementation ...
Are you sure? Could it perhaps be SVR2? (I don’t see any STREAMS stuff that one would
expect for R3).
The interesting feature of this kernel is the
integration of the
Newcastle Connection network
One of my interests is Unix (packet) networking 1975-1985 and that includes Newcastle
Connection. I’ve so far not dived deep into this, but your work may be the trigger for
some further investigation.
My understanding so far (from reading the paper a few years ago) is that Newcastle
Connection works at the level of libc, substituting system calls like open() and exec()
with library routines that scan the path, and if it is a network path invokes user mode
routines that use remote procedure calls to give the illusion of a networked kernel. I’ve
briefly looked at the Git repo, but I do not see that structure in the code. Could you
elaborate a bit more on how Newcastle Connection operates in this kernel? Happy to
communicate off-list if it goes in too much detail.
I note that the repo Readme says that the kernel only does some basic IP networking as a
carrier, but I also see some files in the tree that seem to implement a form of tcp (and
that seem unrelated to the early Unix tcp/ip’s that I have seen so far). Or am I reading
too much into these files?
===
Re-reading the Newcastle Connection paper also brought up some citations from Bell Labs
work that seems to have been lost. There is a reference to “RIDE” which appears to be a
system similar to Newcastle Connection. The RIDE paper is from 1979 and it mentions that
RIDE is a Datakit re-implementation of earlier an earlier system that ran on Spider. Any
recollections about these things among the TUHS readership?
The other citation is for J. C. Kaufeld and D. L. Russell, "Distributed UNIX
System", in Workshop on Fundamental Issues in Distributed Computing, ACM SIGOPS and
SIGPLAN (15-17 Dec. 1980). It seems contemporaneous with the Luderer/Marshall/Chu work on
S/F-Unix. I could not find this paper so far. Here, too, any recollections about this
distributed Unix among the TUHS readership?
11 Aug
11 Aug
3:01 p.m.
Am 11.08.2022 um 08:04 schrieb Paul Ruizendaal:
Maybe the original NC did so,
but here there are numerous additions to
the kernel, including a new syscall uipacket() which is the gateway into
the MUNET/NC implementation. Stuff is in /usr/sys/munet, the low level
networking is in uipacket.c and uiswtch.c which will process RPC
open/close/read/write/exec etc. calls, as well support master and
diskless nodes). The OS code is full of "if (master) {...} else {...}'
code which then redirects detected access to remote paths to the network
handler.
MUNIX was an AT&T SVR3.x implementation ...
Are you sure? Could it perhaps be SVR2? (I don’t see any STREAMS stuff that one would
expect for R3).
It is a hybrid system. I found files and similarities in R1, R2 as
well
as R3 - the C compiler (in my queue) for instance is likely derived (and
heavily modified) from a R1 origin, but in this version itself linked
with a C library where parts are newer, namely from a later released
version (in the update 3-3.1 in tape IS0463P) which I'll add in the
future. I am sure that the kernel libs will then reveal the missing
streams stuff.
I think it was a rolling release which also still contains parts of the
older 16 bit MUNIX for a 68010 with Motorolas FFP lib - the kernel still
contains an obsolete module named m68341 which emulates an incompatible
floating point lib. The 32 bit system here demands a 68020/68881
combination. There are also several QBUS I/O drivers which seem to stem
from the 16 bit systems which likely do no longer access real existing
hardware because the newer systems used a communication controller board
named ICC with an own 68010 processor and a highly stripped down
tailored UNIX (?) on it. This is also on my to-do list.
@readers of TUHS: can anyone say something about m68341? There are
Motorola FFP libs elsewhere on the net, but this appears to be a
complete copro emulation which intercepts the line-F interrupt which I
could not locate so far. Internally, it is pretty much optimized - I
doubt it was cooked at PCS itself, so it is likely a Motorola product.
And no, it has absolutely nothing to do with the embedded controller
MC68341.
Currently I am dissecting the also rather unique a68 assembler which is
a modified Trix/Mical assembler; after that, I'll look into the IS0463P
update.
The
interesting feature of this kernel is the integration of the
Newcastle Connection network
One of my interests is Unix (packet) networking
1975-1985 and that includes Newcastle Connection. I’ve so far not dived deep into this,
but your work may be the trigger for some further investigation.
My understanding so far (from reading the paper a few years ago) is that Newcastle
Connection works at the level of libc, substituting system calls like open() and exec()
with library routines that scan the path, and if it is a network path invokes user mode
routines that use remote procedure calls to give the illusion of a networked kernel. I’ve
briefly looked at the Git repo, but I do not see that structure in the code. Could you
elaborate a bit more on how Newcastle Connection operates in this kernel? Happy to
communicate off-list if it goes in too much detail.
I note that the repo Readme says that the kernel only does some basic IP networking as a
carrier, but I also see some files in the tree that seem to implement a form of tcp (and
that seem unrelated to the early Unix tcp/ip’s that I have seen so far). Or am I reading
too much into these files?
===
Re-reading the Newcastle Connection paper also brought up some citations from Bell Labs
work that seems to have been lost. There is a reference to “RIDE” which appears to be a
system similar to Newcastle Connection. The RIDE paper is from 1979 and it mentions that
RIDE is a Datakit re-implementation of earlier an earlier system that ran on Spider. Any
recollections about these things among the TUHS readership?
The other citation is for J. C. Kaufeld and D. L. Russell, "Distributed UNIX
System", in Workshop on Fundamental Issues in Distributed Computing, ACM SIGOPS and
SIGPLAN (15-17 Dec. 1980). It seems contemporaneous with the Luderer/Marshall/Chu work on
S/F-Unix. I could not find this paper so far. Here, too, any recollections about this
distributed Unix among the TUHS readership?
Good to mention this. I am interested in
such stuff as well.
Regards
Holger
14 Aug
14 Aug
2:40 a.m.
On Aug 11, 2022, at 11:01 AM, Holger Veit
<hveit01(a)web.de> wrote:
I came across a later paper for Unix United / Newcastle Connection. It seems to consider
moving parts of the code into the kernel, to combat executable bloat (the relevant libc
code would be copied into every executable, prior to shared libraries):
https://www.researchgate.net/publication/2997714_The_architecture_of_UNIX_u…
My understanding so far (from reading the paper a few years ago) is that Newcastle
Connection works at the level of libc, substituting system calls like open() and exec()
with library routines that scan the path, and if it is a network path invokes user mode
routines that use remote procedure calls to give the illusion of a networked kernel. I’ve
briefly looked at the Git repo, but I do not see that structure in the code. Could you
elaborate a bit more on how Newcastle Connection operates in this kernel? Happy to
communicate off-list if it goes in too much detail.
Maybe the original NC did so,
but here there are numerous additions to
the kernel, including a new syscall uipacket() which is the gateway into
the MUNET/NC implementation. Stuff is in /usr/sys/munet, the low level
networking is in uipacket.c and uiswtch.c which will process RPC
open/close/read/write/exec etc. calls, as well support master and
diskless nodes). The OS code is full of "if (master) {...} else {...}'
code which then redirects detected access to remote paths to the network
handler. > Re-reading the Newcastle Connection paper also
brought up some citations from Bell Labs work that seems to have been lost. There is a
reference to “RIDE” which appears to be a system similar to Newcastle Connection. The RIDE
paper is from 1979 and it mentions that RIDE is a Datakit re-implementation of earlier an
earlier system that ran on Spider. Any recollections about these things among the TUHS
readership?
>
> The other citation is for J. C. Kaufeld and D. L. Russell, "Distributed UNIX
System", in Workshop on Fundamental Issues in Distributed Computing, ACM SIGOPS and
SIGPLAN (15-17 Dec. 1980). It seems contemporaneous with the Luderer/Marshall/Chu work on
S/F-Unix. I could not find this paper so far. Here, too, any recollections about this
distributed Unix among the TUHS readership?
Good to mention this. I am interested in such stuff as
well.
I found a summary of that ACM SIGOPS workshop. There is a half page summary about David
Russels presentation on “Distributed Unix”:
====
2.4 David Russell: Distributed UNIX
Distributed UNIX is an experimental system consisting of a collection of machines running
a modified version of UNIX.
Communication among processors is performed by a packet switching network built on Datakit
hardware. The network has
a capacity of roughly 7.5 megabits, shared among several channels. Addressing is done by
channel, not by target
processor. Messages are received in the order sent. To the user, communication takes the
form of a virtual circuit,
a logical full-duplex connection between processors.
A virtual circuit can be modeled as a box with four ends: DIN and DOUT control data
transmission, and CIN and COUT
control transmission of control information. Circuits can be spliced together, or attached
to devices. Circuits can
also be joined into groups. A virtual circuit is set up in the following way: a socket is
created with a globally
unique name, and processes then request connections to the named socket. Routing
information is implicit. Virtual
circuits support location transparency, since sockets can move, but not replication
transparency. If a circuit breaks,
it is set up again, although it is up to the user to handle recovery of state information.
Machine failure will destroy
a virtual circuit.
A transparent distributed file system was set up. When a remote file is accessed, a socket
name is generated, which is
used to establish a connection with a daemon at the file server processor. The daemon
carries out the file access on
behalf of the remote user. In conclusion, offloading of tasks was found to work well. The
path manager maintains very
little state. The splice interface between virtual circuits was found to be very
efficient, although UNIX scheduling
was not appropriate for fast setup of circuits.
====
The modeling of virtual circuits sounds like a mid-point between Chesson’s multiplexed
files and Ritchie’s streams.
The file system actually sounds like it could be the RIDE system. Maybe this Distributed
Unix and RIDE are one and the same thing.
(although the original Newcastle Connection paper suggests they are not:
https://inis.iaea.org/collection/NCLCollectionStore/_Public/16/081/16081910…)
Paul
11 Aug
11 Aug
7:32 p.m.
Paul Ruizendaal <pnr(a)planet.nl> writes on the TUHS list today:
> ...
> ... the Luderer/Marshall/Chu work on S/F-Unix. I could not find this
> paper so far. Here, too, any recollections about this distributed Unix
> among the TUHS readership?
> ...
Is this the sought paper?:
@String{j-OPER-SYS-REV = "Operating Systems Review"}
@Article{Luderer:1981:DUS,
author = "G. W. R. Luderer and H. Che and J. P. Haggerty and P.
A. Kirslis and W. T. Marshall",
title = "A distributed {UNIX} system based on a virtual circuit
switch",
journal = j-OPER-SYS-REV,
volume = "15",
number = "5",
pages = "160--168",
month = dec,
year = "1981",
CODEN = "OSRED8",
ISSN = "0163-5980 (print), 1943-586X (electronic)",
ISSN-L = "0163-5980",
bibdate = "Sat Aug 26 08:55:53 MDT 2006",
bibsource = "http://portal.acm.org/;
http://www.math.utah.edu/pub/tex/bib/unix.bib",
acknowledgement = ack-nhfb,
fjournal = "ACM SIGOPS Operating Systems Review",
journal-URL = "http://portal.acm.org/browse_dl.cfm?idx=J597",
}
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3 comments
3 participants
participants (3)
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Holger Veit -
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Paul Ruizendaal