DECsystem-1090 (KL10) power requirements

Tony Duell wrote: Absolutely! None of the changes we intend to make to the KL10 involve any permanent alteration. Aside from the power supply, we want to change two other things: Memory - We have an Ampex 4 megaword ECC memory box for the KI10-style memory bus (which is interfaced to the KL10 through the DMA20 memory bus interface in the I/O bay). However, it consumes massive amounts of power, and is physically huge. The main CPU card cage has two "S bus" memory interfaces (not to be confused with Sun's S-bus which came many years later). For each S bus there is an ECL<-->TTL translator board, and a slot for cabling to the DMA20. I've done preliminary design work on a board to plug into the S bus cable slot and implement the 4 megawords of memory using six 8M*8 SDRAM chips. I'd use a DIMM, but it won't fit mechanically due to the 12.7 mm board spacing. Over 55% of the memory bits will go to waste! Disk and tape I/O - Several companies made Massbus-to-SCSI adapters; most of them only supported 16-bit Massbus transfers for use on VAXen and PDP-11en, but a few of them supported 18-bit Massbus needed for the DECsystem-10 and DECSYSTEM-20. I think I've talked someone who once worked on these things to lend or give me one of the leftover prototype units. I don't have it yet, though, so this part could still fall through. We'll still need to have the capability of using the RP06 (and perhaps the TU78) on occasion in order to deal with standard media.