The PERQ 3 Trivial FAQ!

This isn't so much a FAQ as a list of problems and oddities I've run into with my PERQ-3 (an ICL 3300 Graphics Workstation). It's an attempt to provide some useful information on the machine and to fill the gaps left by the other FAQs.

  1. So What's The Difference Between the PERQ 3 and the PERQ 1/2?

    Just about everything, really... The PERQ-1 and 2 had CPUs constructed from discrete logic, whereas the PERQ 3 is based on the standard 68020 CPU and 68881 FPU combination. The PERQ 3 also runs PNX 300, which is ICL's version of Unix System V R2, whereas PERQ 1s and 2s ran POS (the PERQ Operating System) with a version of PNX based on Seventh Edition Unix as an alternative.

  2. What does it look like?

    The system unit is 150mm wide, 530mm deep and 330mm tall. It's a bit like a rather deep 'mini-tower' case as seen on (around?) PC clones. The monitor is a 21 inch black and white affair. It's 500mm tall, 500mm wide and 400mm deep. The mouse is slightly odd by modern standards - it's a sort of squarish block slightly taller and somewhat shorter than a PC mouse. The three buttons are on the front rather than the top face, and the ball is steel rather than rubber or plastic.
    Some photos are now available.

  3. Right, I've Got A PERQ 3, How Do I Turn It On?

    (I said it was a trivial FAQ...) The PERQ 3 can turn itself off and on - the circuit diagram for this is quite interesting. The mains power is switched via a relay, so you must have the battery connected to power the switching circuitry. You then press the push button on the side of the monitor base - this will cause the fans to start, and the boot up process should commence...

  4. Aaargh, there's a nasty stripy pattern on the display - what's wrong?

    Nothing, honest. The PERQ 3 has a boot process designed to make you think it's broken - it's rather odd. The pattern is the monitor/graphics processor test - it'll go away in a second. Then the machine will appear to thrash the disk for ages, after displaying the 'Graphics Microcode v7.2.0' banner. This is just loading the microcode and kernel, and it takes a while.

  5. How about the funny numbers on the front?

    This is the Diagnostic Display System (yes, really!). It counts up as the PERQ performs various self tests and boots up. You can also run a wider range of tests, controlled by DIP switches on the CPU board. As the documentation says:

    If you are working from the display information,
    make sure the DDS is in place.

    Code  	Meaning
    DEAD  	What it says! Couldn't find a stack area for the boot program. 
    0010	MPU
    0011	Static Memory
    0012	Main Memory
    0013	Video Memory
    0014 	Pager
    0015 	Graphics Processor
    0016 	Floating Point Processor
    0017	SCSI
    0018	DMA
    0019	OMTI Board (SCSI-to-HD/FD interface)
    001A	RS232 (remote comms)
    001B 	RS232 (local comms)
    001C	OSLAN (ethernet)
    001D	Real Time Clock
    001E	CPU Board Data ROM
    001F 	Memory Board Data ROM
    0020	DDS Board OSLAN Address ROM

    I can't find anything after this, but observation suggests

    0213    during microcode loading
    0000 	after successful UNIX boot

    The tests and display are rather more detailed if you set the switches to test mode rather than normal (system) mode.

  6. How Do I Pronounce PNX?

    I'm told it should be 'Pee-nicks'.

  7. How Can I Get My PERQ To Talk To Something Else?

    All this information is guesswork - I haven't got it working yet...
    First, the (allegedly) simple method: procure a null modem cable, connect it between the PERQ and the PC. Set up uucp software at each end. Transfer files as needed.
    Actually, you may find it easier to just use cat to transfer data across the serial line. I have a couple of nasty shell scripts which use shell archives to transfer files and cope with the fact that I seem to intermittently lose a kilobyte or so from large transfers. I could be persuaded to part with them if you really want them...
    In theory, you should be able to use the ethernet connection. You'll need a transciever to connect to the PERQ, a PC network card, a length of thin ethernet cable, two BNC T-pieces, and two terminators. The hardware side is easy - software is likely to be tricky :-)
    The trouble is that the PERQ doesn't speak TCP/IP. It knows something called the Newcastle Connection (slogan: Unixes of the World Unite!), but I can't find any details that would allow me to implement this under Linux, for example... If you get this option working, I'd like to hear about it!

  8. How should I disassemble it?

    These are Tony Duell's hints on how to do this. They're quite long and detailed, so they're on another page.

  9. Why shouldn't I run the demonstration programs?

    On my machine, there are some demonstration programs which load some static images (logos, maps, technical drawings). However, they seem to tend to cause crashes - mostly the machine just locks up, but I got a kernel panic once... Your mileage may vary, naturally. I'm running a 0.J(A) version kernel.

  10. How Do I Turn The Silly Thing Off Again?

    Like all Unix boxes, the PERQ 3 has to be shutdown correctly. As root:

    # cd /
    # shutdown 0
    ... wait for INIT: SINGLE USER MODE ...
    # bye
    The BYE command will sync the discs and power the PERQ down automatically. I think this is impressive, but then I'm easily amused.
    Feel free to specify a longer timeout to shutdown if there are other users on the system (well, you never know...)

  11. Why is the Clock So Important?

    If the real time clock information is corrupted (if the battery is removed, for example) the PERQ 3 will refuse to boot from the hard drive! Hopefully you have a copy of the stand-alone disk utilities floppy (sadu). You can boot with this and set the clock (to GMT). The PERQ should then boot normally again.

  12. So How Does It All Work?

    I recently came across the following interesting document... It's a technical description of the innards of the PERQ 3. Unfortunately, it's a little cryptic without schematics...

  13. Can I Add More SCSI Devices?

    There is a connector at the back which gives you access to the SCSI bus. Unfortunately PNX doesn't appear to have devices to access new SCSI devices: there is no obvious pattern to the device numbers, so it looks as if they didn't allow for this possibility.

Can anybody think of anything else to add? (Obviously yes, but what else?)

to be continued...

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This page written by Peter Maydell (