21 May
1998
21 May
'98
1:43 p.m.
From: Daniel A. Seagraves [mailto:DSEAGRAV@toad.xkl.com]
Wait a minute! ECC uses 2 bits?
That leaves 9.
9, 18, 27, *36*.
Hmm!
Something 36 bits maybe?
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There were several types of ECC schemes. Some worked at the byte level,
some by the word. PDP memory boards commonly uses 22 bit words (16 data
+ 6 ECC), or accessible as 11 bit byte (8 data + 3 ECC). Memory boards
based around Intel 256K DRAM controllers also supported this type of ECC
(I think it was the 8206/8207 chipset?). The Intel ECC scheme was neat
because it would scan for errors during refresh cycles, "bit scrubbing".
Memory is vague, but I believe the 11 bit ECC byte was a Reed-Solomon
type ECC pattern?
Jack Peacock