• Please review our updated Terms and Rules here

How were PDP-8 networked?

R

rorypoole

Veteran Member
Joined
Dec 8, 2004
Messages
585
Location
UK, Surrey
how were pdp8's in the same computer room networked, in the 1960 and 1970s? was is just rs232 or custom bus adapters?
 
I don't think "8"s were ever networked in the 1960's or early 1970's You moved magnetic media between machines, or punched paper tape. I can't even find any evidence for using them as peripherals to mainframes, where as the pdp-11 was certainly used in that manner in the 1970's.

When I was at College, Newcastle University implemented NUNET using PDP-11s and dedicated phone lines...

http://www.staff.ncl.ac.uk/roger.broughton/1994snap/docs/DSC_0015.htm

http://history.cs.ncl.ac.uk/anniversaries/40th/images/nunet2/index.html

Later at the Natural Environmental Research Council (NERC), so from 1983-88, in conjunction with the Science and Engineering Council (SERC) we used PDP-11's to build packet switched networks using the GPO's (UK Post Office who ran the phones in the UK) "Experimental Packet Switched Network" protocol. I found some info here....

http://www.chilton-computing.org.uk/ca/literature/newsletters/forum_81_83/p81g.htm

but again mostly as RJE workstations...
 
Many times I have flipped past the section in the 8/e maintenance manual for the DB8E interprocessor buffer. There's your high speed hardware for interfacing omnibus 8's together directly. I guess one wrote their own code to do whatever with it.

Lou
 
I have seen a lot of pics of pdp8 setups using more than one pdp8? where that all just sharing rack space or DB8E interprocessor buffer's?

The straight 8 had one strange computer peripheral, a second straight 8 as a GPU!! or as DEC called is a DISPLAY-8 or type 338 programmed buffered display? it must have used something like the DB8E interprocessor buffer, but for the negibus straight 8, I have found very little info on the DISPLAY-8.

what are the options for vector graphics on a pdp8?
http://www.vintage-computer.com/vcf...are-the-options-for-vector-graphics-on-a-pdp8

I am not going to build two straight 8's I have two Harris HD1-6120-9 "PDP-8 on-a-chip" the chips can be used to build a pdp8e comparable computer and can be clocked up to 5.1mhz so should make a good GPU for the straight 8!

Harris HD1-6120-9 "PDP-8 on-a-chip"
http://www.vintage-computer.com/vcf...20-9-quot-PDP-8-on-a-chip-quot&highlight=6120

DISPLAY-8 Brochure 1967
http://bitsavers.informatik.uni-stuttgart.de/pdf/dec/graphics/338_Display_Brochure_1967.pdf
 
I've seen mention of DECnet/8 online, but I know nothing more about it. It'd be awesome to get some sort of networking stack working with several PDP-8s.
 
Looks like DECnet was for pdp-11's and is 8 years too new!!
http://en.wikipedia.org/wiki/DECnet

"DECnet is a suite of network protocols created by Digital Equipment Corporation, originally released in 1975 in order to connect two PDP-11 minicomputers. It evolved into one of the first peer-to-peer network architectures, thus transforming DEC into a networking powerhouse in the 1980s. Initially built with three layers, it later (1982) evolved into a seven-layer OSI-compliant networking protocol."
 
Last edited:
rorypoole said:
Looks like DECnet was for pdp-11's and is 8 years too new!!
http://en.wikipedia.org/wiki/DECnet

DECnet is a suite of network protocols created by Digital Equipment Corporation, originally released in 1975 in order to connect two PDP-11 minicomputers. It evolved into one of the first peer-to-peer network architectures, thus transforming DEC into a networking powerhouse in the 1980s. Initially built with three layers, it later (1982) evolved into a seven-layer OSI-compliant networking protocol.
Click to expand...

PDP-8s were used well into the 80s though. Thus, DECnet could have been ported to RTS-8. That's what it looks like here, anyways.

http://www.classiccmp.org/pipermail/cctalk/2008-October/076945.html
 
Could be as simple as multi-console cards with ports directly linked between machines as a cheap interprocessor buffer. I think it was less machines talking to eachother and more just multiple machines sharing the same rack to save space.
 
g4ugm said:
I can't even find any evidence for using them as peripherals to mainframes
Click to expand...

They were used as communications front-ends, comms concentrators, and remote job entry systems. That was what the type 680
communications multiplexer was designed for. The 338 display control is a little brother to the 339 and mostly just draws a series
of vectors from a display list in core. It is not a general-purpose processor at all.
 
My 8/e was a communication front end to a decsystem10. When we got it, it was filled with cards from DCA (Digital Computer Associates.) I have all the manuals and prints, but I saved only one interesting piece, the AFP-8 Ascii Front Panel. It's a card that replaces the 03/04 console TTY interface. It has a mode where programmer's panel functions can be performed from the TTY. It was amusing to me at one time, but I use regular KL8e and KL8JA now.

Lou
 
Al Kossow said:
They were used as communications front-ends, comms concentrators, and remote job entry systems. That was what the type 680
communications multiplexer was designed for. The 338 display control is a little brother to the 339 and mostly just draws a series
of vectors from a display list in core. It is not a general-purpose processor at all.
Click to expand...

Do you have anu more info on the 338 and 339 display control?
 
Coincidentally I stumbled on this page a few days ago. Search for "PDP" on the page.

http://members.ozemail.com.au/~bconlon/ttopics.htm

I have _no_ idea how and if these PDP-8's where interconnected or not. But the picture is tantalizing:

cover.jpg
 
very interesting, the 3 straight 8's would have to have been connected in some way to share data? also the straight 8 was only about a year old then!

http://www.racingandsports.com.au/racing/racingfeatures.asp?f=featurearticles-tote04

"For the technical man, it is an electronic totalisator using three PDP-8 computers."

"In the accompanying picture there are eight "scanners" in the control room.
Each "scanner" holds the bets of 64 selling machines, so even such a small, compact control could provide for over 500 ticket selling windows."
 

Attachments

  • tote.jpg
    tote.jpg
    50.7 KB · Views: 1
Last edited:
Old thread, but I've got one of the DCA AFP* PCB's. Has anybody got any info on it?

Sherman Foy
 
You must log in or register to reply here.
Back
Top