Lisa I/O Board ROMs

[sigma7]

As of 2020, there are 5 common I/O Board ROM variants

• 1/5 - Twiggy : 341-0138
• 2/5 - 400K : 341-0290
• 2/5 - 800K : 341-8001

• 2/10-400K : 341-0281
• 2/10-800K : 341-8003

The 2/10-800K ROM was not patched correctly when updating from 400K to 800K circa 1988. The consequence is that this ROM will often fail to re-format a floppy that has previously been formatted. BLU has a "zero floppy" function that clears the formatting on a floppy (not just erase the data), after which a 2/10 with this ROM can successfully format it.

Recently, the 2/10-800K error has been located and corrected, and a ROM variant created that is "universal" in that it checks to see if the drive is 400K or 800K (so the ROM does not need to be changed when changing the drive). A similar variant has been made for the 2/5 3.5" drives.

So this adds two more variants that are designated:

• 25SSDSM6 (2/5 400K & 800K) - attached
• XLSSDSM6 (2/10 400K & 800K & re-formatting fix) - attached

Finally, there is a dual Twiggy & 3.5" drive ROM for the Sapient Technologies 2/5 I/O Board, which permits changing between Twiggy and 3.5" drive ROMs using a jumper on the board. This is a double-size ROM, so is a 28 pin 2764. The other I/O ROMs are 24 pin 2732s.

Conceivably one could make a dual Twiggy & 3.5" ROM for the 2/10 as the board hardware has provisions for this option, but AFAIK a Twiggy compatible ROM hasn't been made for the 2/10.

edit: removed version letters
edit: found part number for XL800K
edit: added part number for 2/5 800K

[sigma7]

Here is a preliminary list of the latest versions of each (still working on confirming these):

• 1/5 - Twiggy : 341-0138


• Rev F


• 2/5 - 400K : 341-0290


• Rev B


• 2/10-400K : 341-0281


• D


• 2/10-800K : 341-8003


• C

The "M6" in the names of the universal 400k/800k SSDS ROMs is the version.

edit: updated to match highest revs at http://bitsavers.org/bits/Apple/Lisa/firmware/

[compu_85]

I tried the XLSSDSM6 in my 2/10 XL, which has an 800k drive and found it works great, and is able to re-format floppies in Mac OS 6 without trouble.

I also put 25SSDSM6 in my 2/5 with a 400k drive, and on a quick test I found no issues either.

Thanks,

-J

[compu_85]

Another note: UniPuls+ Unix seems to know what to do with these ROMs and an 800k drive!

Thanks,

-J

[jamesdenton]

Here is a preliminary list of the latest versions of each (still working on confirming these):

• 1/5 - Twiggy : 341-0138


• Rev F


• 2/5 - 400K : 341-0290


• Rev B


• 2/10-400K : 341-0281


• D


• 2/10-800K : 341-8003


• C

I have a 2/5 with the 341-0290B ROM installed, and have found that with a FloppyEmu device, 800KB disk images work OK. I can read/write/format without issue (so far). Uniplus even shows it as a 'Microdiskette with 2 heads'. I do not have a physical 800k drive to test with.

[ried]

I have a 2/5 with an I/O board that features an Apple / Sun Remarketing ROM part number 341-8001, presumably for its 800K floppy drive.

[pl212]

I have a chip marked 341-0841D, labeled:

"Lisa 2/10 XL 400K Drive"