PDP-8 /e/f/m memory

On Aug 14, 2006, at 8:54 PM, Ethan Dicks wrote: >> > Why not use a pair of 62256s? 32Kx16 and ignore 4 bits. It'd even >> >> be >> >> > easy to use a Dallas DS1210 or something like it to provide battery >> > backup. >> >> I'd probably do something like what the SBC-6120 does... use some >> typical 486 >> motherboard cache SRAM. Cheap, and relatively easy to find. :) >> >> You'd end up with one or two chips to do 32k x 12. > > 32Kx8 are easy to find as old cache RAM. They are not, however, low > power, and would not be the best solution if you wanted to hang a > battery off of them. OTOH, unless you are using paper tape software > only, chances are you have a mass storage device and are booting into > OS/8 and don't really need battery backup.

True, but I think the idea there was to duplicate the functionality of core, i.e. the nonvolatility in this case. That said, though, I've not found 486 motherboard cache memory to be particularly easy to find. I did, however, buy a box of about 80 6264 chips on eBay a few months ago for fifteen bucks. And 62256s are still manufactured, as far as I'm aware.