Hi,

I've been digging a bit deeper into Mac hardware issues (Apple's Acrobat
docs) to find out what is wrong with the floppy driver on some machines.

So far, I have tested the driver successfully on SE/30, IIsi, IIci and
Quadra 700. I had no success on a Performa 630 and a (docked) Duo 280, and
I got a total of two test reports (anybody out there?) for a Quadra 630 and
a Quadra 650 -- both negative.

Well - it looks like all '040 Macs with the notable exception of the Quadra
700 (*) are currently out of luck when it comes to floppy access. All these
machines  (2nd generation Quadras/Centrises/'040 Performas) have an engine
called SWIM II, stuffed together with other units on a multifunction chip,
and the SWIM II is different from the SWIM when it comes to IWM
compatibility. The only thing the internet has to say about the SWIM II is
that it predates the SWIM III.

At the moment I cannot say whether the problems are related to a different
initialization sequence, or whether the entire access pattern has changed.
The funny thing is that the SWIM .Sony driver is still present in the ROMs
and does not differ significantly from what I see on the Q700. On the other
hand, the Duo 280 has an additional .Sony driver of ~6k in the System file.

The bittom line is that the driver should work as-is on every '030 Mac
except the IIfx, and on the Quadra 700. I don't know about the original Mac
II with 800K drive -- any testers?

So, if anybody's best friend works for Apple and hasn't been laid off...

	hauke


(*) This is actully a strange pattern. When I left university in '94, I
thought about getting a discount LC III as a replacement for my SE. Looking
at the size of my desk at home, I decided to stick with a compact Mac, and
got a 2nd hand SE/30. Great little machine, and one of the few that
supported NetBSD/mac68k "out of the box" at the end of '94.
Two years later, I got a 2nd hand Q700. After some months, I started
hacking on floppy access, not knowing I had picked the very only '040
machine with a 1st generation SWIM chip. I'd never gotten anywhere wit,
say, an LC 475 or a Q650...



--
"It's never straight up and down"     (DEVO)