3 ms·
not really like scsi - that's more like usb with a central controller. more like VME - a bus that looked alot like a 68k bus, but supported multiple masters wit
by convolvatron 3y ago
not really like scsi - that's more like usb with a central controller. more like VME - a bus that looked alot like a 68k bus, but supported multiple masters with a protocol to negotiate temporary ownership to assert a transaction.
there was a single address space. so every board had a set of dip switches to give it its address. which was always a big source of pain
I can't imagine apple shipping a computer product like that, so maybe you get the high bits based on what slot you're in and a config eprom to do discovery?
- flenserboy 3y agoI could see them using something like they did with NuBus — something similar to the declaration ROMs could make this sort of configuration work nicely, as long as part makers played according to the specs.
- leejoramo 3y agoInteresting. I suspect if Apple had done this they would have had someway for the cards to auto-negotiate. A few years after the Jonathan prototype, I remember fighting with the DIP switches on PC ISA cards and setting the the correct IRQs, and then seeing a friend drop in a NUBUS card into their Macintosh II and the hardware was magically configured. I wonder if NUBUS could have multiple masters?
- rbanffy 3y agoApple II cards knew which slot they were in and could have small ROMs with simple IO functions.