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? ------- 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