Matt Thomas writes:
 > At 01:59 PM 5/21/97 -0400, Brian Hechinger wrote:
 > >what difference does true-parity RAM versus psuedo-parity RAM make in the
 > >PC world?  we had a SUN SPARCstation 2 at work die, and if i act quick i
 > >can get 32M of 30-pin 4M true-parity (9 chip) simms, if there is a good
 > >reason to do this i'll grab them.
 > 
 > True parity can do ECC with the 430HX (Triton II) chipset.

Maybe I'm missing something here but surely parity ram will add an
extra bit which will catch any single bit error and any odd number of
errors but not even numbers of bit errors, and this would truly be
parity.

Now if I decide to use more redundant bits say to implement a 4-3
hamming code then I can correct any single bit error.

Surely parity is an error detection method, not an error fixing
method.

This is not to say, however, that the ECC ram is not referred to as full
parity. It just seems a strange way of saying ECC

Just my $0.02 worth

Alex.

-- 
Alex Barclay			E-mail: alex@vsys.com
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