Q-Bus Memory Diagnostics and Repair

Noel Chiappa jnc at mercury.lcs.mit.edu
Fri Sep 9 18:11:13 CDT 2016

    > If your CPU is an 11/73 (which can directly 'access' [hate that verbism
    > :-] all of memory from ODT, unlike the 11/23 which is restricted to the
    > bottom 256KB), try playing around with a failing location, and its
    > alternative, directly, and see if a store of random data into one can be
    > read back directly from the other

Note: The 11/'73' CPU powers up with the cache enabled, even for ODT!

So if you write xxx into some location, if you then read it back, you will get
the correct data even if the memory location is busted - the CPU is getting
the (correct) data from the cache. To have your 'memory' reads and writes
actually go to the memory, you need to turn off the cache:

  17777746/ 02000 

Note that starting the machine does an INIT, which will again enable the

    > I'll start the Computer History wiki page for this board with that info.



Currently has only the memory chip info, I'll add the config stuff as I get it
doped out.


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