henry (08/13/82)
Early this spring we were looking around to buy some more memory for our 11/44, which at 1/4 meg was just a little bit low on bytes. We checked with a number of outfits selling 1-meg boards, and most of the prices were scandalous, like $12000 (those are Canadian dollars, but even so...). We found only one 1-meg board with a reasonable price, that being Motorola's. One problem: the Motorola board has parity but no ECC. We are just a little bit paranoid about soft errors in big RAMs, and this didn't make us happy. Just when things looked like an impasse, and it looked like we'd have to settle for 1/2 meg instead, I got a quote from National Semiconductor on their 1/2 meg board, the NS44F. University price, in US$ FOB plant, was $2618! Delivery 4-6 weeks, full ECC, reasonably fast. At this price we could afford 1 meg in half-meg boards, with the added bonus that one broken board wouldn't cripple our system. (It's really nice to have more than one of something...) We bought two of them. Delivery was as promised. After some hassles (possibly our fault) the first time we tried to install it, the boards just dropped right in and ran. That was several months ago; they're still running. The NS44F seems to be a good solid board. The board does ECC by the *byte*, not the word, which not only eliminates extra complexity to handle byte writes, but gives considerable extra error-proofing. The RAMs (they are 64K's) are all socketed, and there is a burned-in spare RAM in an extra socket on each board. Just about everything of interest can be set by DIP switches, including two-way interleaving if you have two boards (we haven't bothered with this yet). The comparison with our 1/4 meg Dec board is particularly striking (it has soldered RAMs, no spare, options set by jumpers, ECC on pairs of words [not even individual words!], and it's loaded with PAL logic that isn't easy to repair in the field). Our only complaints about the NS44F are that the twits didn't send us schematics with the boards, and the manual doesn't say anywhere just how much power the things use. Going from 1/4 meg to 1+1/4 makes a tremendous difference to performance under Unix. Loads that used to cripple our system now have rather minor impact. The users found the change very noticeable, and have voted with their feet: our usage is up considerably. The difference is particularly spectacular when using screen-oriented programs, since they don't get swapped out any more. In fact, we don't swap at all these days -- our swap area gets used only for sticky-bitted texts. Since it's clear that we are underutilizing the memory, and our current bottleneck is the disk heads, we are looking at using some of that memory either as a pseudo- disk or as a vastly enlarged buffer cache. The two NS44F's were probably the best $5000 we ever spent. I don't know of anybody else using NS44F's hereabouts, but just about everybody at U of T buys memory from National, for good quality and low price. National's memory system marketing is at (408)736-7132.