Re: 11/40 misbehaviour

From: John Holden (johnh_at_psych.usyd.edu.au)
Date: 08/16/04

  • Next message: Hoff Hoffman: "Re: VAXstation 3100 strange-ness!" 
    Date: Mon, 16 Aug 2004 09:13:42 +1000

    Rich Alderson wrote:

    > Runs intermittently. Was running for hours at a time, now dies in under 2
    > hours.
    >

    When it 'dies', does it halt, or lock up so that none of the console
    switches work unless you press the 'start' key to do a bus reset. If the
    latter, then it's hanging up in the microcode. If it runs for a couple
    of hours, then halts, then a strong possibility is memory (remember that
    every memory access is destructive, and the data must be written back).

    Try zeroing all memory (assuming 64Kb)

                    175770 5000 clr r0
                    177772 5020 clr (r0)+
                    177774 776 br .-2

    Start at 175770, and let it run until it halts (a faction of a second).

    Then, load a trap catcher http://www.psych.usyd.edu.au/pdp-11/hints.html
    and finally a continuous loop:-

            0774 12706 mov #770,sp set the stack
            0776 00770
            1000 000777 br . infinite loop

    Start at 0774, then wait. When it halts, look at the adddress to see if
    it trapped or halted. The display will show the halt adrress + 2, and if
    it was via the 'trap catcher', then the display will show the vector + 4

    If the address is 10, then it was a bus error trap. Examine the stack at
    address 766, which will be the address of where it was when the trap
    happened.

    If the address is 14, then it's a reserved instruction. Check as above.

    If the address displayed at halt was 30, then there was a power fail
    interrupt and you have power supply problems

    If the address is above 1006, then check if it contains only a single
    bit after correcting the location by subtracting 2. So a halt at 10002
    or 20002 might indicate problems with an address line (or decoding in
    a memory module).

    Also, check the original contents of location 1000, which should still
    be 000777. If it has changed (usually by one bit), then it's a memory
    problem. You may pick up or loose a memory bit depending on the memory
    design and where the fault is (data latch, memory timing, noise margin
    etc)

  • Next message: Hoff Hoffman: "Re: VAXstation 3100 strange-ness!"

    Relevant Pages

    • Re: Program analysis
      ... strcpying from an uninitialised memory. ... You also don't know if strcpy() won't halt since you don't ... set sock ...
      (comp.programming)
    • Re: Best practice using large objects in foreach
      ... I dont't think there would be no halt because the objects remain in gen1. ... And on the server side GC is concurrent. ... it's always imperative to Dispose() as fast as you can. ... so you will see the memory usage ...
      (microsoft.public.dotnet.languages.csharp)
    • Re: [RFC v5][PATCH 2/4] intel_txt: Intel(R) TXT reboot/halt shutdown support
      ... attempting to reboot or halt the system will cause the ... TXT hardware to lock memory upon system restart because the secrets-in-memory ... flag that was set on launch was never cleared. ...
      (Linux-Kernel)
    • Re: Maximum size of a background file
      ... background will cause his computer to grind to a halt. ... Essentially - you are using up your memory to display it. ... The larger that image file size - the more memory it uses to keep it visible ...
      (microsoft.public.windowsxp.general)
    • Re: Boot & reboot after POST+ blue screen
      ... the next time you get a Blue Screen your computer will halt and you can write down all the information. ... However I can't boot to Safe Mode. ... "Leonard Grey" wrote: ... Now your computer will 'crash' and display a blue screen. ...
      (microsoft.public.windowsxp.perform_maintain)