Re: IWM and un-suitable drives for Macs

[dempson@actrix.gen.nz (David Empson)]

Patrick Schaefer <patrick.schaefer@topmail.de> wrote:

> A few days ago we had a discussion about connecting a 5.25" Apple II
> drive to a Mac. Here is a description of the IWM chip I just found
> browsing the caltech ftp server:
> 
> ftp://apple2.caltech.edu/pub/apple2/dev/iwmstuff

A very interesting article - it looks like Neil Parker did a fair amount
of disassembly of the IIgs firmware to work out more information about
the operation of the 3.5" drive, and how it is used by the IIgs.

For anyone else who hasn't seen it yet: it contains descriptions of the
IWM registers, the 3.5" drive control and status registers, and some
assembly code for using the IWM directly to access a 3.5" drive.

I knew most of what was in here from reading various Macintosh and Apple
II doucmentation from Apple, but he has gone a little further than what
was publically documented.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand