Yeah, not much more info on those links either. Just, kind of "here is this thing, and some photos of it, it's cool, you know."
This is interesting:
http://www.digibarn.com/collections/systems/apple-lisa1/lisa1-prototype/apple_glm_boards.jpg as it shows it in use with a much larger board underneath it, but can't tell what it is, and certainly it could be the original Lisa's design, but it wouldn't fit in the chassis.
Oh well. I can guess about the serial ports, but they're not necessary from the point of view of the Lisa as internal communication on the expansion slots would be sufficient. So those are meant to be external communications ports.
Since the Lisa has 3 slots, you could add 3 of these to one and you'd have a 4 core system. It's likely IMO the serial ports are meant to turn the Lisa into a unix server. They're also fast enough for LocalTalk (nee Appletalk back then), but possibly that wasn't what they're for because the board says 1982 and we didn't have AppleTalk until later.
The diagonal slant on the outside of the card shows it was intended to live inside a Lisa chassis as that matches other cards, but it's actually too deep to fit in a Lisa 1 or Lisa 2. So that means a different Lisa chassis would be needed and we never saw much larger Lisa prototypes.
I don't know how much RAM is on these boards, hard to read the chips, I think it says HM4864, which are 64x1bit DRAM? but there's 18 of them, which means 16 bits plus two parity. (
https://i.ebayimg.com/images/g/CaMAAOSwvTpaAeEk/s-l1600.jpg form
https://www.ebay.com/itm/DRAM-64kx1-Dynamic-RAM-64k-x-1-200ns-HM4864-3-MB8264-20-CERAMIC-DIP-8-pieces-/261614573015 and
https://www.datasheetarchive.com/HM4864-2-datasheet.html )
There's a row of empty holes on the board labeled U1B-U14B, and extras at U1D-U4D - possibly for expansion RAM as that's another 18.
So that would give you 128K since there's 16 bits, and 256K if both were populated or just 64K as is in the photo.
Likely there's some shared memory that's accessible to the Lisa expansion slot bus to allow the CPU on the CPU board to communicate with these.
The ROM sockets say 2764, those are 8Kx8 and two of them, so those aren't boot ROMs, but rather for the 68000 on the card, possibly some portion of the space there was shared over the expansion slot to server as an expansion card ID, or perhaps another ROM was used elsewhere on the board for that.
So that's a lot of RAM for this card. Lisa RAM cards were 512K, so that's half of one of the Lisa's RAM cards! Possibly if they planned for higher density RAM they could add a lot more.
More than enough to spin off another process to one of these CPUs, and memory page the process from main memory to this board, from say a Unix process and also act as a pair of TTYs. Possibly more than one process could be affinitized (if that's a word) to one of these depending on how much RAM it needed. But likely there'd be no MMU at all - and perhaps it would work even better as, since each process would run on its own card and page/swap to main memory, and then to ProFile/Widget, it would provide a higher level of security (unless more than one process was sent simultaneously to share memory in one card.)
So if they could have shrunk these boards to fit the chassis, or made the chassis bigger, this would have effectively made the Lisa a very nice Xenix/UniPlus server. Not quite a mini, but certainly a server for upto 8 terminals. Or perhaps they may have planned a much larger chassis with many expansion slots instead of just 3 and you could plug in other cards such the as two port or AppleNet cards as well, and they wanted to keep that compatible with existing expansion slot cards.
Anyway, just all conjecture on my part, but still, plausible, so my crazy guess is they were planning for a large Lisa server, most likely for some kind of Unix.
Well either that, or this was the original CPU board for the Lisa and then RAM, Z8530 were moved to RAM boards and an I/O board respectively.
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Topic: Anyone know what this is? "Great Little Machine" prototype (Read 11379 times)