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What, specifically, is a LAB-8?

SpaceHobo

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Dec 10, 2021
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17
Location
London, UK
I got into the PDP8 series through a friend who inherited a PDP12 in good condition, and I've been digging into the history of the LINC a little. In particular, I found this answer from a Lincoln Labs person who went on to Digital: https://youtu.be/xT_5PcrVI9Q?t=5790 Long story short, the LINC-8 was rather a clumsy kitbash of the PDP-8 and LINC, and when he was on jury duty he had the spare time to work out how to do it properly, and that became the PDP-12.

But from here, I have questions:

The 12 seems to be a PDP-8/I with a LINC and a rather graceful switchover between the two (right down to runtime code being able to flip back and forth, which kind of blows my mind given the PDPs used twos-complement (like "The Universe" according to one of the MIT HAKMEMs) and the LINC was ones-complement). The 12 looks like the first model to get floating point hardware (due to its huge backplane, perhaps?).

But the LAB-8 seems to be a PDP-8/e in PDP-12 livery (lime peel and chartreuse), with the LINC's I/O facilities (Is that where the vc8e name came from? Is that the same part in the 12?) but no actual LINC processor integration. Am I right about that? Is there any documentation about the history and development of the LAB-8s? Was there more than one in the series, or was it just the LAB-8/e and that was it? Did the Lab-8/e have a special card to adapt to the display and the analogue inputs, and would that card work in any omnibus 8/e?
 

vrs42

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Nov 24, 2009
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621
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Beaverton, Oregon
The 12 seems to be a PDP-8/I with a LINC and a rather graceful switchover between the two (right down to runtime code being able to flip back and forth, which kind of blows my mind given the PDPs used twos-complement (like "The Universe" according to one of the MIT HAKMEMs) and the LINC was ones-complement). The 12 looks like the first model to get floating point hardware (due to its huge backplane, perhaps?).
You may be right. I think the FPP-12 can hang on any Posibus with Data Break, but I haven't tried it :).

But the LAB-8 seems to be a PDP-8/e in PDP-12 livery (lime peel and chartreuse), with the LINC's I/O facilities (Is that where the vc8e name came from? Is that the same part in the 12?) but no actual LINC processor integration. Am I right about that? Is there any documentation about the history and development of the LAB-8s? Was there more than one in the series, or was it just the LAB-8/e and that was it? Did the Lab-8/e have a special card to adapt to the display and the analogue inputs, and would that card work in any omnibus 8/e?
The green color I think means it's meant to be lab equipment, and there are other colors for other intended uses.

The LAB-8/E has no LINC features. It has a display and the analog conversion stuff to interface to your lab equipment, but I wonder if they didn't think the LINC was obsolete by then. At any rate. you're just expected to write your code with PDP-8 instructions. There were similar options for non-Omnibus PDP-8 machines, but I don't know how popular they were.

The VC8E is not as nice as the PDP-12 interface to the VR14. Basically it plots points, but nothing else. Software has to generate the characters as points, in a relatively compute-intensive way. I think there were some additional option cards for automatic line and character generation, but I know next to nothing about them.

But yes, I believe the cards for the LAB-8/E should work without problems in any Omnibus machine.

The Omnibus FPP card is pretty much an 8/A thing (due to it's hex height), though.

The whole PDP-12 "made out of autonomous co-processors" mindset is almost absent in the PDP-8 world.

Vince
 

czunit

Experienced Member
Joined
Aug 7, 2015
Messages
146
You may be right. I think the FPP-12 can hang on any Posibus with Data Break, but I haven't tried it :).

Yep, the 8/I I had used an FPP12 from a pdp12 that I could not "get up the steps" (the 12's were too big for a station wagon). Fortunately the 8's and the FPP12 were in their own H960's which would fit in a 1970's Ford wagon.

There were two models if I recall and I had the bigger one. I think it was almost half a rack of flip chips, that plus the RK8 controller filled a H960.

It hooked up to the Posibus, and had an amazing display board as well. I sold it along with the 8/L... 15 years ago on Ebay? Wow.
 

ftcnet

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May 4, 2019
Messages
109
Location
BC Canada
lab8e.jpg - Click image for larger version  Name:	lab8e.jpg Views:	0 Size:	70.5 KB ID:	1236078
This is a LAB 8/e from the Technikum 29 Living Museum. Visible components are PDP 8/e, 3x TU56 dual tape drives, VR-12 scope display, PC04 paper tape reader/punch, analog I/O panel and ASR-33 console terminal. The analog I/O panel typically connected to internal Omnibus options. The AD8-E (A231, A232, A840) connects to the analog I/O panel. The VC8-E (M869, M885) controls the VR-12 scope display.

The system pictured above has no disk storage, but did include the TC08 DECtape control which used DMA transfers instead of programmed I/O like the TD8E (M868 ) 'simple' DECtape control. The TC08 connects to the 8/E via KA8E Positive I/O (M8350) and KD8E Data Break (M8360) interfaces.
 
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