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Reading MAC 800K disks.
Ernst,
>>>>>> "Jesse" == g sightler <g.sightler@genie.geis.com> writes:
>>
>> Jesse> Actually, it would be possible to do this without the MAC
>> Jesse> floppy drive, if someone was willing to put the many hours
>> Jesse> necessary into it. <g> Seriously, it is VERY timing
>> Jesse> sensitive (which rules out the possibility of running it
>> Jesse> under any mulitasking OS), but it can be done with the
>> Jesse> right amound of hacking/patience.
>>
>> Jesse> In fact, the early MAC emulators for the Amiga did this
>> Jesse> rather well (of course, they had to shut off multitasking
>> Jesse> to do it :).
>>
>> Clifford T. Matthews replied:
>>
>>Well it certainly won't happen between now and when 2.0 comes out.
>>Even then I'm not sure that the PC has the same sort of control over
>>the floppy disk that the Amigas did. After 2.0 comes out we'd
>>probably be willing to pay some $$ to get this functionality, but I'd
>>also guess that just a simple program to read 800k Mac disks on a PC
>>would also generate some revenue, which then begs the question "if
>>it's doable, why hasn't someone done it?" Specifically, why hasn't
>>someone written a program for the PC which reads an 800k formatted
>>floppy (writing is much less important).
>>
>Had the same thoughts and had someone look into the SWIM chip of Mac's
>(Super Woz Integrated Machine) - handles diskette I/O. It is IMPOSSIBLE to
>do this on a PC without hardware. The 800K Mac drives (and all drives
>since then) use a variable spindle speed of the disk drive's motor. This
>motor on PC drives can only be switched on or off. There is no software
>control over its speed. When the speed cannot be controlled there is no
>way to decipher the information that comes from the controller.
Actually, the Amiga was unable to change the speed of the drive's motor
either. This is why it was such a TIMING sensitive thing (and a very
difficult hack to program, from what I've been told :).
Although, as we have now been told by others here, it still wouldn't be
possible on a PC (they don't give as much control over the floppy as the
Amiga).
||||| Jesse D. Sightler |||||