PDP-11/45 RSTS/E boot problem

Paul Koning paulkoning at comcast.net
Mon Feb 4 15:15:18 CST 2019

> On Feb 4, 2019, at 3:43 PM, Noel Chiappa via cctalk <cctalk at classiccmp.org> wrote:
>> From: Wayne S
>> it might be a wonky filesystem. ...
>> The corruption probably came because the entire disk was going bad.
> This theory is contradicted by the fact (mentioned several times, including in
> the message you were replying to) that doing a plain 'ls' bombs, but 'sleep
> 300 &; ls' works fine.

That translates into "the problem depends on the physical address of the code being executed".

The obvious answer is bad memory.  Another possibility occurs to me: bad bits in the MMU (UISAR0 register if I remember correctly).  Bad memory is likely to show up with a few bits wrong; if UISAR0 has a stuck bit so the "plain" case maps incorrectly you'd expect to come up with execution that looks nothing at all like what was intended.


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