PDP-11/45 RSTS/E boot problem

wrcooke at wrcooke.net wrcooke at wrcooke.net
Sun Jan 20 21:11:34 CST 2019


> On January 20, 2019 at 3:56 PM Fritz Mueller via cctalk <cctalk at classiccmp.org> wrote:
> 
> 
> 
> I'm technically curious, now, about the failure modes of these sorts of DRAMS. I guess in addition to stuck bits, there are also potential decode fails (show up on address test, but not ones/zeros) and some errors that have history-dependence, perhaps internal latches (show up on random data test, but not address or ones/zeros.) I'd guess also there might be potential for crosstalk, noise, and "fading bit" type issues as well? Will have to see after I make the next round of repairs if there are still additional problems that the MAINDEC flags that my simplistic diag isn't shaking out.
> 

Jack Ganssle wrote a couple of articles about memory testing and failure modes.  They may be useful or at least interesting.
http://www.ganssle.com/articles/aramrom.htm
http://www.ganssle.com/articles/ramtest.htm

Will

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