The ICL PERQ (aka. Three Rivers PERQ)

Doing some research/thinking for a little retro project I’m looking at, I remembered the old PERQ workstation - c1980. It’s time-frame fits right in my own era although I think I only ever saw one working at that time.

The Wikipedia entry is informative:

But I was just wondering if anyone saw or used one, or even tinkered with it’s (modifiable) microcode - which did seem to be something that a few people did do back then.

(I’m vaguely toying with the idea of my own microcoded cpu engine thing which is why I’ve looked at this)



I saw one, gathering dust as I recall, at Edinburgh Uni in about '83/84. My other half did use them, at South West Gas in Keynsham, possibly doing data analysis and visualisation in Fortran (but she can’t remember…)

Edit: Massive PERQ history at Chilton Computing. Also it seems PNX (one of several available operating systems had an optimising Fortran compiler.

Edit: it turns out there are three sections to CC’s Perq history, under the heading of Single User Systems, the name of the procurement project.

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What I always found quite interesting about the PERQ: It obviously shares some commonalities with the Alto, and, indeed, early ads list in the software section some of the PARC tools, like the Bravo word processor. However, as far as I can tell, the production machines were based on Bell Labs software. Has anyone insight in what happened to the initial plans and why there was this switch?

What I found strange, nobody seems to have the portrate
screen after that on a desk top computer. It was all games
on the telley. Ben.
PS: Sad about the TV in Wales. They covered up proof of “mind control” of the public by the *** again, to turn people in to harmless **** and ***.

For a few years in the late 1980s and early 1990s, the rotary Radius displays were somewhat popular on the high-end of low-end Macs. Apple also released a portrait monitor of their own, I think, in 1989. It looked promising for a few years, but then it somehow faded away.

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(I’ve just realised - right in front of me right now is a rotatable 1600x1200 LCD display, and it’s in portrait orientation.)


I know some you can flip some, but not mine. Those computers had the idea of screen was a piece of paper
and the software tried keep it that way for the display.
Windows gives you umm windows, just no control over the size of the box." What you see is what you" get may sell computers, but you endup with resizing everything with the next version of the OS. Having to buy new old software again does not help. I have yet to figure out how to get a 80x24 text display full screen like under dos box.
Is there a PREQ Emulator around? What I have seen have dead links to the program?

Accidentally, my main display is also a rotary one. When I got it (about 10 years ago), I was quite split about in what orientation to use it. On the one hand, I always wanted a page display, on the other hand, software interfaces became wider and wider and more or less unusable in portrait mode. In the end, Adobe won.

Mind that classic MacOS always favored portrait mode in default window sizes and windows never span the screen horizontally in landscape mode. (You could even argue that the toaster Macs provided a one third slice of a view into what was a virtual portrait view port that wasn’t to be achieved with that kind of cheap hardware and respective screen sizes. It seemed quite logical to extend this into a full page portrait mode at that time, at least more than just sizing up that view in landscape, unless you got the holy grail, a two-page monitor.)

And, yes a PERQ emulator (with software!) would be nice.

There’s an emulator by Josh Dersch which runs on .NET here

Seen running here:

and a page about running it here.

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I read yesterday that the initial SAU1 workstation from Apollo (1981) had a portrait format display. Presumably there was some influence from the Alto project


We had a demo PERQ or two at Brown University CS, while evaluating a purchase for a teaching lab. While we ended up buying Apollo and Sun, the PERQ was amusing. One odd feature was the BITBLT cursor (an image of a bee when the system was busy, if I remember correctly). At least in the version that was running on the machine I touched, it was apparent that the bounds checking wasn’t quite adequate, as you could fling the cursor at the side of the window and end up overwriting some important part of the O/S and crash the system.


Every time this post revives, it reminds me of the AT&T BLIT graphics terminal, previously mentioned here:

The BLIT was infamously originally called the JERQ, a play on PERQ. As remembered by Rob Pike:

(Relatedly, if anyone has a line on a Teletype 5260, the commercial version of this terminal, I am interested.)


While Blit remained more of a footnote regarding “regular” computing, it enjoyed some use in the DMD (dot-mapped display) mainly used for document viewing by AT&T and Teletype, if I got my history right.

Regarding Rob Pike, mind his paper “The Blit: A Multiplexed Graphics Terminal” (Bell Laboratories, 1983):

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That’s the Teletype 5260 that I mentioned. It used (much to the disappointment of those involved with the Blit) the ill-fated and under-performing Bell 32000 processor. I’m looking for one regardless!

I played with an ICL Perq at Marconi Electronics, IC Division, Lincoln (UK). The version we had was for evaluation as a chip design workstation, however Apollo Domain machines were chosen.
I believe the Perq we evaluated used the AMD 2900 bitslice chips to implement the instruction set (the Motorola 68000 devices used in later versions were not yet available)