Floppy disk emulator for Lisa from Steve Chamberlin on 2015-02-28 (lisalist1)

From: Steve Chamberlin <steve.chamberlin_at_email.domain.hidden>
Date: Sat, 28 Feb 2015 09:00:14 -0800 (PST)

I've been working on a floppy disk emulator for the Lisa, and thought the folks here would be interested. I previously developed some hardware called Floppy Emu for the vintage Macintosh, which emulates 400K, 800K, and 1440K floppies as well as the Apple HD20 hard disk. Recently I started thinking about what might be necessary to add Lisa support, since the 400K and 800K floppy mechanisms are actually the same between the Lisa and the Mac. In theory it should be possible to add Lisa support purely through firmware changes, using the existing hardware.

With the help of some very kind Lisa experts and a borrowed Lisa 2/10, I've been running some tests and doing some experiments, using BLU as well as a custom floppy test program. You can read about the progress so far here:

http://www.bigmessowires.com/2015/02/21/apple-lisa-floppy-emulation/
http://www.bigmessowires.com/2015/02/23/lassoing-the-lisa/
http://www.bigmessowires.com/2015/02/24/lisa-emu-day-3/

Currently with the Lisa test firmware, the Floppy Emu works on a Lisa 2/10, for reading and writing emulated 400K and 800K Macintosh floppy disks under Macworks. But it's too slow to be very useable, and I think there are repeated low-level errors happening that are slowing down floppy I/O. The current Lisa test firmware doesn't seem to work at all on the Lisa 2/5.

Once emulation of Macintosh floppies is working smoothly under Macworks (I hope), I plan to add additional firmware support for native Lisa format floppies, so the hardware could be used to boot the Lisa and run under the Lisa Office System.

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Received on 2015-03-01 14:46:43