🚀 go-pugleaf

In article <4009@phri.UUCP>, roy@phri.UUCP (Roy Smith) writes:
> In <9451@attctc.Dallas.TX.US> torch@attctc.Dallas.TX.US (Jay Finger) writes:
> > Writing a parity bit to a RAM chip that doesn't exist (the empty 9th space
> > on your 8-bit SIMM) certainly doesn't hurt anything.
> 
> 	As long as the missing chip is the same speed as all the other chips
> in the SIMM.  Don't go mixing 80ns chips with 70ns spaces or you'll get
> memory heartburn! :-)
> -- 
> Roy Smith, Public Health Research Institute

If that 9th chip is missing how can it have a speed.  The idea here is that
the CAS, RAS, WR, etc signals are just going off into never-never land.  The
parity bit will never get written (since there's nothing to write it into).
When you read it back there's no chip to drive the data line, so it either
comes back random or it'll float low or high all the time.  It doesn't matter
because if you're using 8-bit SIMMS you've parity disabled so the error is
never caught.

------------------------------------------------------------------------------
Jay Finger  (214) 298-5915            |If all you do is treat symptoms, you'll
UUCP:   {ames, mit-eddie}!attctc!torch|continue to see more symptoms forever.
DOMAIN: ames!torch@attctc.dallas.tx.us|                    -- Tom van Vleck
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