26 Jan
2020
26 Jan
'20
2:04 p.m.
I noted with much pleasure that the main bitsavers site is back up, and that at some point
it has added a full set of scans of “Datamation”. The Feb 1975 issue contains an article
from Dr. Fraser about Spider and the network setup in Murray Hill early in 1975:
http://bitsavers.org/pdf/datamation/197502.pdf
For ease of reference I have also temporarily put the relevant 4 pages of the issue here:
https://gitlab.com/pnru/spider/blob/master/spider.pdf
I find the graphic that shows how Spider connected machines and departments the most
interesting, as it helps understand how the pro’s and con’s of Arpa Unix might have been
perceived at that time.
The more I read, the more confused I become whether the “Pierce loop” was a precursor to
“Spider” or a parallel effort.
The facts appear to be that John Pierce (https://en.wikipedia.org/wiki/John_R._Pierce)
submitted his paper to BSTJ in December 1970, essentially describing a loop network with
fixed size short datagrams, suggesting T1 frames. It is quite generic. In February 1971
W.J. Kropfl submits a paper that describes an implementation of the ideas in the Pierce
paper with actual line protocols and a TIU. In October 1971 C.H. Coker describes in a 3rd
paper how to interact with this TIU from a H516 programming perspective.
Several Spider papers mention that the project was started in 1969 and that the first
Spider link was operational in 1972. The team appears to be entirely different: the h/w is
credited to Condon and Weller, and the s/w to Frazer, Jensen and Plaugher. The Spider TIU
is much more complex (200 TTL chips vs. 50 in the Kropfl TIU). The main reason for that -
at first glance - appears to be that in the Spider network the TIU handled guaranteed in
order delivery (i.e managed time outs and retransmissions), whereas in the Kropfl
implementation this was left to the hosts.
It would seem logical that the latter was an evolution of the former, having been
developed at the same site at the same time. A 1981 book seems to take that view as well:
“Local Computer Network Technologies” by Carl Tropper includes the text "Spider
Spider is an experimental data communications network which was built at the Bell
Telephone Laboratories (Murray Hill, New Jersey) under the direction of A. G. Fraser. A
detailed description of the network is given by Fraser [FRAS74]. This network was built
with the notion of investigating Pierce's idea of ...” The chapter is titled “The
Pierce loop and its derivatives”. This is a much as Google will give me - if somebody has
the book please let me know.
On the other hand, the Spider papers do not mention the Kropfl network or Pierce’s paper
at all. The graphic in Datamation appears to show two Kropfl loops as part of the network
setup. Yet, this is described in the accompanying text as "4. Honeywell 5l6: Supports
research into comunications techniques and systems. The machine has a serial loop I/O bus
threaded through several labs at Murray Hill. Equipment under test is connected either
directly to the bus or to a minicomputer which is then connected to the bus. Also avail-
able are graphics display terminals and a device that can write read-only memory chips.”
Maybe this is a different bus, but if it is the same as the Kropfl loop, to call it a
“serial loop I/O bus” suggests it was a parallel effort unrelated to Spider.
Does anybody on the list recall whether Spider was a parallel effort or a continuation of
the earlier work?
26 Jan
26 Jan
4:56 p.m.
the pierce loop had its own protocol on its own wire.
that meant it could only be local-area. the PL was
in operation on a packard-bell 516 when i arrived
at the labs in june '66. carl christensen was the
software person for both the loop and the 516.
i assume that pierce and condon were the hw
guys, but that was before my time.
spider was similar, but was designed to run on
the standard telephone T1 lines. thus, the whole
idea was more wide-area. the major draw back
of spider, and probably the reason it was never
really used, was that it couldnt make a connection.
all connections were pre-created at boot time.
a lesser reason was that the controller was a
tempo computer that no one loved. the system
software sucked. quickly it became unmaintained.
i think tempo went out of business. anyway, the
spider controller was the first and only tempo
computer that i saw or even heard of.
On Sun, Jan 26, 2020 at 6:05 AM Paul Ruizendaal <pnr(a)planet.nl> wrote:
I noted with much pleasure that the main bitsavers
site is back up, and
that at some point it has added a full set of scans of “Datamation”. The
Feb 1975 issue contains an article from Dr. Fraser about Spider and the
network setup in Murray Hill early in 1975:
http://bitsavers.org/pdf/datamation/197502.pdf
For ease of reference I have also temporarily put the relevant 4 pages of
the issue here:
https://gitlab.com/pnru/spider/blob/master/spider.pdf
I find the graphic that shows how Spider connected machines and
departments the most interesting, as it helps understand how the pro’s and
con’s of Arpa Unix might have been perceived at that time.
The more I read, the more confused I become whether the “Pierce loop” was
a precursor to “Spider” or a parallel effort.
The facts appear to be that John Pierce (
https://en.wikipedia.org/wiki/John_R._Pierce) submitted his paper to BSTJ
in December 1970, essentially describing a loop network with fixed size
short datagrams, suggesting T1 frames. It is quite generic. In February
1971 W.J. Kropfl submits a paper that describes an implementation of the
ideas in the Pierce paper with actual line protocols and a TIU. In October
1971 C.H. Coker describes in a 3rd paper how to interact with this TIU from
a H516 programming perspective.
Several Spider papers mention that the project was started in 1969 and
that the first Spider link was operational in 1972. The team appears to be
entirely different: the h/w is credited to Condon and Weller, and the s/w
to Frazer, Jensen and Plaugher. The Spider TIU is much more complex (200
TTL chips vs. 50 in the Kropfl TIU). The main reason for that - at first
glance - appears to be that in the Spider network the TIU handled
guaranteed in order delivery (i.e managed time outs and retransmissions),
whereas in the Kropfl implementation this was left to the hosts.
It would seem logical that the latter was an evolution of the former,
having been developed at the same site at the same time. A 1981 book seems
to take that view as well: “Local Computer Network Technologies” by Carl
Tropper includes the text "Spider Spider is an experimental data
communications network which was built at the Bell Telephone Laboratories
(Murray Hill, New Jersey) under the direction of A. G. Fraser. A detailed
description of the network is given by Fraser [FRAS74]. This network was
built with the notion of investigating Pierce's idea of ...” The chapter is
titled “The Pierce loop and its derivatives”. This is a much as Google will
give me - if somebody has the book please let me know.
On the other hand, the Spider papers do not mention the Kropfl network or
Pierce’s paper at all. The graphic in Datamation appears to show two Kropfl
loops as part of the network setup. Yet, this is described in the
accompanying text as "4. Honeywell 5l6: Supports research into
comunications techniques and systems. The machine has a serial loop I/O bus
threaded through several labs at Murray Hill. Equipment under test is
connected either directly to the bus or to a minicomputer which is then
connected to the bus. Also avail- able are graphics display terminals and a
device that can write read-only memory chips.” Maybe this is a different
bus, but if it is the same as the Kropfl loop, to call it a “serial loop
I/O bus” suggests it was a parallel effort unrelated to Spider.
Does anybody on the list recall whether Spider was a parallel effort or a
continuation of the earlier work?
4:58 p.m.
On Sun, Jan 26, 2020 at 03:04:34PM +0100, Paul Ruizendaal wrote:
That is fascinating, what a walk down memory lane!
5:50 p.m.
Ken Thompson via TUHS writes:
the pierce loop had its own protocol on its own wire.
that meant it could only be local-area. the PL was
in operation on a packard-bell 516 when i arrived
at the labs in june '66. carl christensen was the
software person for both the loop and the 516.
i assume that pierce and condon were the hw
guys, but that was before my time.
spider was similar, but was designed to run on
the standard telephone T1 lines. thus, the whole
idea was more wide-area. the major draw back
of spider, and probably the reason it was never
really used, was that it couldnt make a connection.
all connections were pre-created at boot time.
a lesser reason was that the controller was a
tempo computer that no one loved. the system
software sucked. quickly it became unmaintained.
i think tempo went out of business. anyway, the
spider controller was the first and only tempo
computer that i saw or even heard of.
Oh wow, that jogs loose some more stray memory cells. Found the Tempo
manual on-line which had a front panel picture. There was one of these
sitting in a rack near the window in the 516 lab back when we were in
building 2. Not sure if it ever made it to building 7, might have been
tossed. This thing a telephone handset hanging off of it.
Nice to see the networked IC test system that I mentioned the other day
in the datamation article on page 52. It was on the loop, not the spider,
when I worked on it.
Jon
9:26 p.m.
On 26 Jan 2020, at 17:56, Ken Thompson <ken(a)google.com> wrote:
the pierce loop had its own protocol on its own
wire.
that meant it could only be local-area. the PL was
in operation on a packard-bell 516 when i arrived
at the labs in june '66. carl christensen was the
software person for both the loop and the 516.
i assume that pierce and condon were the hw
guys, but that was before my time.
Ah, so the Pierce loop was operational several years before the papers were submitted to
BSTJ. That explains a lot.
spider was similar, but was designed to run on
the standard telephone T1 lines. thus, the whole
idea was more wide-area. the major draw back
of spider, and probably the reason it was never
really used, was that it couldnt make a connection.
all connections were pre-created at boot time.
The Spider report has a section on the protocol for making/breaking connections
dynamically, but this is not used in the surviving programs which hard code a destination
(channel). I wondered about that when Noel first found the sources for ’nfs’. Maybe this
connection protocol was planned but never implemented.
a lesser reason was that the controller was a
tempo computer that no one loved. the system
software sucked. quickly it became unmaintained.
i think tempo went out of business. anyway, the
spider controller was the first and only tempo
computer that i saw or even heard of.
The video that Sandy Fraser recorded has a segment about that at 25:30. Apparently, just
before Christmas Ed David gave him $60K budget to buy a computer to build the Spider
switch. The catch was that it had to be delivered before New Year. With the above
sentiment in mind it was perhaps no surprise that Tempo had a unit sitting on the shelf
that could be shipped in that time frame.
On Sun, Jan 26, 2020 at 6:05 AM Paul Ruizendaal
<pnr(a)planet.nl> wrote:
I noted with much pleasure that the main bitsavers site is back up, and that at some
point it has added a full set of scans of “Datamation”. The Feb 1975 issue contains an
article from Dr. Fraser about Spider and the network setup in Murray Hill early in 1975:
http://bitsavers.org/pdf/datamation/197502.pdf
For ease of reference I have also temporarily put the relevant 4 pages of the issue
here:
https://gitlab.com/pnru/spider/blob/master/spider.pdf
I find the graphic that shows how Spider connected machines and departments the most
interesting, as it helps understand how the pro’s and con’s of Arpa Unix might have been
perceived at that time.
The more I read, the more confused I become whether the “Pierce loop” was a precursor to
“Spider” or a parallel effort.
The facts appear to be that John Pierce (https://en.wikipedia.org/wiki/John_R._Pierce)
submitted his paper to BSTJ in December 1970, essentially describing a loop network with
fixed size short datagrams, suggesting T1 frames. It is quite generic. In February 1971
W.J. Kropfl submits a paper that describes an implementation of the ideas in the Pierce
paper with actual line protocols and a TIU. In October 1971 C.H. Coker describes in a 3rd
paper how to interact with this TIU from a H516 programming perspective.
Several Spider papers mention that the project was started in 1969 and that the first
Spider link was operational in 1972. The team appears to be entirely different: the h/w is
credited to Condon and Weller, and the s/w to Frazer, Jensen and Plaugher. The Spider TIU
is much more complex (200 TTL chips vs. 50 in the Kropfl TIU). The main reason for that -
at first glance - appears to be that in the Spider network the TIU handled guaranteed in
order delivery (i.e managed time outs and retransmissions), whereas in the Kropfl
implementation this was left to the hosts.
It would seem logical that the latter was an evolution of the former, having been
developed at the same site at the same time. A 1981 book seems to take that view as well:
“Local Computer Network Technologies” by Carl Tropper includes the text "Spider
Spider is an experimental data communications network which was built at the Bell
Telephone Laboratories (Murray Hill, New Jersey) under the direction of A. G. Fraser. A
detailed description of the network is given by Fraser [FRAS74]. This network was built
with the notion of investigating Pierce's idea of ...” The chapter is titled “The
Pierce loop and its derivatives”. This is a much as Google will give me - if somebody has
the book please let me know.
On the other hand, the Spider papers do not mention the Kropfl network or Pierce’s paper
at all. The graphic in Datamation appears to show two Kropfl loops as part of the network
setup. Yet, this is described in the accompanying text as "4. Honeywell 5l6: Supports
research into comunications techniques and systems. The machine has a serial loop I/O bus
threaded through several labs at Murray Hill. Equipment under test is connected either
directly to the bus or to a minicomputer which is then connected to the bus. Also avail-
able are graphics display terminals and a device that can write read-only memory chips.”
Maybe this is a different bus, but if it is the same as the Kropfl loop, to call it a
“serial loop I/O bus” suggests it was a parallel effort unrelated to Spider.
Does anybody on the list recall whether Spider was a parallel effort or a continuation of
the earlier work?
9:55 p.m.
Minor correction to Ken's post, it was a Honeywell 516, not Packard Bell.
I lived on this machine for years. Carl Christensen was one of the
Explorer Scout advisors along with Heinz which is why we got to play with
their machines.
The Pierce loop was up an running by the time that I showed up which was
maybe 1969 or 1970. I don't recall ever meeting Pierce. My recollection
is that the serious digital hardware guys in the group were Dave Weller,
John Sheets, John Schwartzwelder & John Camlet. And Joe Condon had his
fingers in everything and made sure that everything reeked of cigarette
smoke.
I'm guessing that work was being done on Spider while the loop was in use,
again, because I remember the rack with the tempo, phone handset, and Tek
display near the 516. And I'm pretty sure that I remember Sandy messing
with it on occasion; I think that he's the one that demonstrated to me that
there was an option to hook the handset up to a DAC that was on the program
counter or something, so one could listen and figure out if things were
running properly. I think that there was a rack panel with a rotary switch
that one could use to select the handset source.
It sounds like a number of the devices that were connected to the loop
migrated to Spider after I left.
I'm guessing that when the article says that there were graphics display
terminals connected that those were the GLANCE G terminals that I mentioned
in an earlier post. And, the PROM programmer makes sense too; I think that
this was in the room shared by John Camlet and Dan Belinski and was used to
program the TTL PROMs that contained the GLANCE G microcode. This sticks
out in my mind because of the time that John and I tracked down and fixed a
microcode bug.
The rest of the network configuration is unfamiliar to me, again as it came
after I left. I do remember that Max Matthews had a pile of DDP-224s because
his lab was yet another cool place to hang out. The 516 hooked to the IC test
system was one of my projects. It wasn't in area 10, I believe that it was in
area 20 under Iverson. It had its own loop, sounds like it was later replaced
by Spider.
Not sure where it fits into the evolution of things, but I recall that our
department was split. Hank Macdonald handled the Murry Hill end of things,
and Cher Cutler the Homdel end. I don't remember exactly what was going on
at Homdel (other than blinding drivers on the Garden State Parkway), but I
recall that they had run a whole bunch of optical fiber underground I think
using the same ductwork that went to the fountains which were not purely
decorative, they were the chillers for the HVAC system too.
Jon
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5 comments
4 participants
participants (4)
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Jon Steinhart -
Ken Thompson -
Larry McVoy -
Paul Ruizendaal