rcbaem@eutrc3.urc.tue.nl (Ernst Mulder) (08/08/89)
Hello World ;)
I asked this before on the net, but I will ask it again because I got
no response.
The disk drives I use on my Macintosh aren't standard Apple drives.
(Sorry Apple, but at the time I couldn't afford better Drives) These Drives
are 800K Drives, but they work a bit different, apparently, than standard
Apple 800K Drives. I guess the Disk Driver doesn't recognise them as Apple
Drives.
The fact is the stepping rate is much slower. (As I read somewhere the Drive
itself tells the Mac it's ready stepping, so the Mac can give a new command
to the Drive) I think the Drive would make much less noise (At the present
you can hear it stepping three floors down) when the stepping rate is
increased, and that's exactly what I want to do.
Two ways I can think of:
1) Modify the Hardware of the Drive, which seems very difficult to me,
2) Modify the Disk Driver. I copied the .Sony DRiVeR from the Roms to a
file to disassemble it. But I still haven't fount which routine does the
stepping. The second thing is, when I copy the isolated .Sony DRVR into
my System file, I think the Mac still uses the one in the ROMs. Should I
use the ROV# resources to let the System use my version of .Sony? Or do
I have to write an INIT which first closes the .Sony in ROM and then opens
my .Sony DRVR? Looking at the code it seems the DRVR puts jumps to
certain routines in a jump table in the System Globals. I don't know
whether the DRVR sets these jumps to the .Sony DRVR in RAM when I override
the ROM .Sony. If not, this could be solved by writing an INIT which
modifies one of these vectors, and let it point to a routine of mine,
residing as a Locked object somewhere in the System Heap... (The latter
doesn't seem very proper to me...)
Does anyone at Apple, reading this, know how the .Sony Disk Driver
works? And which vector (if any) points to the stepping routine?
BTW, it doesn't have to work on all Macs, I only want it working on my
Private Mac, until I have the money to either buy a HD, or proper Drives...
PLEASE help me, I'm driving my neighbours and roommate CRASY. :)
Any hints would help, I'm quite good at interpreting assembly code.
Ernst.
>
Disclaimers: I don't know any.