SLAC 8080-based terminal of 1976

In comp.os.cpm for Feb 2 2009, in a thread "Re: early dates for CP/M", Glen Herrmannsfeltz mentioned an 8080 graphics terminal design developed for internal use by SLAC, the Standford Linear Accellerator Center, a nuclear research facility in California. Here's the discussion plus follow-up by me. - Herb Johnson

SLAC terminal

Glen, feb 6 2009 and forward:

Then in 1977 I was working in the lab next to the person working on this one:

That was an 8080 based graphics terminal, again with unlabeled DRAM for storage. In text mode, it had a scroll wheel on the side that would scroll the screen at scan line resolution. The wheel was heavy enough to start it spinning and then stop it at the desired position. In graphics mode, it emulated the tektronix graphics terminals, with no scrolling.

[Notes on the publication by Herb: the Web link above links to a PDF document on the development of the terminal:


"The Stanford-SLAC Video Graphics Terminal VGT" was a project to create a low-cost grahics and text terminal (81 X 37 lines) based on an 8080 with 2127 DRAM memory and an NTSC video monitor. The Prototype was constructed in Fall 1975, the report and upgrade in Spring 1976. "A large part of the graphics software was stolen from a graphics program for the 8008". The terminal was intended to be used with an IBM 370 and the WYLBUR text editor. "In GRAPHICS mode the VGT is the closest we could come to being a complete Tektronix 4013 simulator."

Rough schematics are in the document which show all chips and most connections. Source code was published with the document but is not part of the PDF file.

A companion document (not yet obtained) is referenced:

"The Design of a Low Cost Video Graphics Terminal", Proc . Third Annual Conf . on Computer Graphics, July 14-16 1976, University of Pennsylvania . Also available from the Stanford Linear Accelerator Center as SLAC PUB .1715

(Submitted to 1976 National Computer Conference, document is dated Feb 1976. Parts costs are dated "September 1975".)] Herb Johnson wrote in reply:

> Glen, this is a nice bit of history. The schematics in the manual > referenced, are dated 8/1975 and 1/1976. The document states a > prototype was developed (presumably completed) in the fall of 1975. > That's a pretty early use of the 8080. Thanks for calling it out.

That is earlier than I would have thought. Well, they were still working on it summer 1977. But as I understand it the unlabeled RAM was donated by intel, so they could easily have gotten early 8080's, too. Herb Johnson wrote:

> Glen, I pulled those dates from the actual PDF document. Since you are familiar with it, I'd appreciate it if you looked it over and commented on the dates yourself. If I reference the document on my site, I'd be glad to include your comments as well. thanks! Glen:

The dates are presumably right. The software was still being worked on in summer 1977. I believe that was by a summer student, so it might be that not much had been done on it since summer 1976.

The author of the paper is the Chairman of the Board of Directors of the Computer History Museum. The original document had a pocket in the back for a microfiche listing of the software. The listing seems not to have gone into the PDF. It might be that LJS would have a copy, though.

>Thanks for the reply and comments. The drawings had two dates, and the document mentions two versions.

>There seems to be some interest in early 8008 and 8080 systems these days. SOme of that interest seems to be "what if those systems caught on?" Often, however, very early 8080 or 8008 systems are research, one-off, or academic devices which are not intended to be turned into products. It's a misunderstanding of the difference between business activity and research activity. But they help to establish what was available or known at the time, before someone created or promoted a product in a business sense. glen

I believe this one was intended as an internal SLAC product.

They would produce them for their own use, but otherwise it was a research project. That is, research is funded for what is needed, and supports the overall physics research.

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