Msg: 5971 *Conference*

08-17-95 16:57:57

From: TRACY ALLEN

To : RON WIESEN

Subj: REPLY TO MSG #5969 (UNDELETE -- COLD START RECOVERY)

Ron,
  That's interesting about the F8E9--F91F area.  I'll keep my eyes open.
Actually, I'm just reading and responding to your message on an M100 that I
just got in for repair, that was supposed to have a bad modem (their cable was
bad, not the modem!!).  But I've forgotten how to deal with the small screen.
I usually sign on from my Mac and have a 64k scrollback buffer.
  
  Re: the byte written into memory at cold start.  I recall that it just tests
the first byte in each 8k segment, at 8k intervals.  The byte does not normally
get permanently altered.  The OS reads in the exiisting byte, then writes some
different data (I forget what, maybe the complement) and then writes back the
original data.  the purpose is to test how many RAM modules (8k each) are
installed, and compare that number to what it found at the previous test.  If
the amount of installed memory has changed (new chip, loose chip, bad chip) the
machine cold starts.  Anyway, there should not be any change in data left at
those addresses.  I found out about it, because if you load the RAMRST line on
the bus, sometimes there is a glitch and the locations get zapped, or sperted.
 
-- Tracy