II SI?

[trag]

http://cgi.ebay.com/Apple-820-0305-01-Mac-IIsi-NuBus-Adapter-Card_W0QQitemZ170200781142
here is the PDS to Nubus adapter for the IIsi

Yeah, except that one is missing the metal frame. Unless my memory is really out of whack, the PDS to NuBus adapter for the IIsi has a metal frame to help support it.

 

[trag]

A few other thoughts. As is commonly known, the oscillator on the IIsi can be replaced and the machine clocked up to at least 25 MHz. Some have taken it to 27 or 28 MHz. A few MHz may not sound like much, but at those overall speeds, each MHz is a substantial percentage of the total.

The NuBus adapter could probably support multiple slots, but it would require major modifications. Once you have the NuBus circuitry at all, most of the work is done. The modifications would be to actually get the additional connectors wired to the board, and to wire the slot ID pins properly, adn finally to identify some additional unique interrupt lines to connect the slots' interrupt to--one interrupt per slot. I imagine the chipset has the interrupts available on some of the pins, since the chips are probably the same or very similar to those used in the IIci.

It would be interesting to try wiring larger memory capacity into the built-in 1 MB bank of memory. Again, given the simiilarities to the IIci, it should be able to take 64 MB in that bank.

But then, once you've gone to all the trouble above, you'd just have a IIci, so really, I guess it's kind of silly.

 

[LCGuy]

And at the end of the day, I'd still be afraid of killing that little PSU, like I said, even back in the day those little PSUs weren't known to be the best. You'd need an extra auxiliary power supply for sure.

 

[ianj]

IIsis are nice machines; it was actually my first 68K Mac. If you install the RAM Muncher INIT and keep an eye on your extensions, the performance isn't too bad. I haven't used mine much since I got my Quadra, but they're not bad at all, especially for free. The floppy port is a nice bonus, too.

 

[IIsi]

If you set your disk cache to over 1 MB the iisi gets a speed boost, since the 1 MB built in ram is then used as VRAM, since you're pushing the VRAM data into the 1 MB of onboard memory, and this has a latch that the RBV chip can use to access that ram separately.

 

[Bunsen]

The NuBus adapter could probably support multiple slots

Well, that is indeed interesting }

 

[Franklinstein]

I've got a 2-NuBus dealie in one of my IIsis. It came with a fairly expansive SuperMac video setup. The two cards fit because they partially overlap, with the (custom-made) bottom card's port protruding through the top card's back slot cover.

I doubt it would be easy to install two normal NuBus cards in the thing, unless the bottom card didn't need external connectivity.

 

[Bunsen]

Are you sure they are actually two separate Nubus cards, rather than one Nubus card and a rather large daughtercard?