Thread
Format 800K MFS with 64K ROMs
Hate tro bring up this old post, but I'm going to try and get that nested volume manager together for you 
EDIT: on a further note, This may be an issue because I can't seem to find a copy of Mega-whatever C that he uses, and the code is.. incomplete in some places. I'll look at it further when my eyes arent so blurry.
EDIT: on a further note, This may be an issue because I can't seem to find a copy of Mega-whatever C that he uses, and the code is.. incomplete in some places. I'll look at it further when my eyes arent so blurry.
UPDATE ON DRIVE COMPATIBILITY:
I have now tested the following 3.5" External Drives with a 64K ROMs:
Apple UniDisk 3.5" – MFD-51W mechanism
Introduced in September 1985 with the HD20
This drive works with the Liron interface bypassed without the HD20 INIT.
This drive interestingly will not work with the 800K Ext. Drive cable (with or without the HD20 INIT).
However, it will work with the 400K Ext. Drive cable as well without the HD20 INIT.
Macintosh 800K External Drive – MFD-51W-10 mechanism
Introduced January 1986 with the Mac Plus
This drive does not work with any cable without the HD20 INIT.
Apple 3.5" Drive – MFD-51W-03 mechanism
Introduced September 1986 with the IIGS
This drive works with any cable but the 800K Ext. Drive cable and the UniDisk cable causes continuos eject, without the HD20 INIT.
(The FDHD Superdrive MFD-75W-01G also works like an 800K Apple 3.5" Drive as well)
What's interesting here is that the UniDisk for the Apple II was released well before the 800K Drive was available for the Mac and could be used with or without the HD20 INIT with 64K ROMs, but the internal Liron interface card disabled it from otherwise working with the Mac. The newer 800K Ext. Drive did not have an interface card, so it seems Apple deliberately disabled an updated version of the Sony drive (-10) and changed something about the DB-19 cable to further disable it, in case the UniDisk drive-type mechanism (which is otherwise compatible) ended up in it, so it would still only function with the HD20 INIT. I'm sure in part, this kept anyone from attempting to continue to use MFS with the 800K drives even though it is easily possible -- particularly where the 128K was concerned which could not use HFS. What better reason to upgrade to a Mac Plus?
I have now tested the following 3.5" External Drives with a 64K ROMs:
Apple UniDisk 3.5" – MFD-51W mechanism
Introduced in September 1985 with the HD20
This drive works with the Liron interface bypassed without the HD20 INIT.
This drive interestingly will not work with the 800K Ext. Drive cable (with or without the HD20 INIT).
However, it will work with the 400K Ext. Drive cable as well without the HD20 INIT.
Macintosh 800K External Drive – MFD-51W-10 mechanism
Introduced January 1986 with the Mac Plus
This drive does not work with any cable without the HD20 INIT.
Apple 3.5" Drive – MFD-51W-03 mechanism
Introduced September 1986 with the IIGS
This drive works with any cable but the 800K Ext. Drive cable and the UniDisk cable causes continuos eject, without the HD20 INIT.
(The FDHD Superdrive MFD-75W-01G also works like an 800K Apple 3.5" Drive as well)
What's interesting here is that the UniDisk for the Apple II was released well before the 800K Drive was available for the Mac and could be used with or without the HD20 INIT with 64K ROMs, but the internal Liron interface card disabled it from otherwise working with the Mac. The newer 800K Ext. Drive did not have an interface card, so it seems Apple deliberately disabled an updated version of the Sony drive (-10) and changed something about the DB-19 cable to further disable it, in case the UniDisk drive-type mechanism (which is otherwise compatible) ended up in it, so it would still only function with the HD20 INIT. I'm sure in part, this kept anyone from attempting to continue to use MFS with the 800K drives even though it is easily possible -- particularly where the 128K was concerned which could not use HFS. What better reason to upgrade to a Mac Plus?