On Thu, Feb 16, 2023 at 11:28 AM David Schmidt via cctalk <
Generally, a ProFile driver that is otherwise
unspecified will be 5MB
). There is a
different card (ROM?) as you found out that will matter for 5 vs. 10MB
variants and driver files.
For the Apple ///, there isn't a different Profile interface card, and
there's no firmware on the card. It's all a matter of what SOS driver is
used. I thought the newer SOS driver supported both 5MB and 10MB drives,
but perhaps I'm mistaken. The drivers generally come from the Apple ///
System Utilities disk and System Utilities Data disks.
For the Apple II, there's an interface card that is used for either the
Profile 5MB or 10MB, but the early firmware 341-0271A, only knows about the
5MB Profile, and also doesn't work with interrupts, so it's not suitable
for the Apple IIgs. The same card, but with 341-0299B firmware, supports
both 5MB and 10MB Profiles and works on the Apple II, II+, IIe, and IIgs.
There are a bunch of places on the internet that claim that you have to use
341-0271A firmware on the Apple II card if you have a 5MB Profile, but that
is flat out wrong. The 341-0299B firmware should be used with both 5MB and
10MB Profiles. It will also work with third-party drives that support
Profile protocol but may have different sizes, potentially up to 32MB.
The firmware _inside_ the Profile is strange in that it doesn't actually
KNOW the size of the Profile it's installed into. At power up, when the
drive reads the home block, the drive size is stored there. That's done
when the drive is formatted. There is different formatter firmware for 5MB
and 10MB drives.
The Apple II Profile interface firmware contains a lot of dead code. Some
of it looks vaguely like reasonable code, but some of it is clearly junk.