[comp.sys.acorn] Mac drives are variable speed

rkl@and.cs.liv.ac.uk (06/14/91)

In article <1991Jun11.160020.8493@ira.uka.de>,
angelo@i41s16.ira.uka.de (Angelo Schneider Betr.Prechelt) writes:
>  patrick@sideways.gen.nz (Pat Cain) writes:
> 
>>  The ability to read high density PC discs would be useful to a lot more
>>  people than the ability to read Mac discs. 

> Ha, Ha, Ha!
> I' know about 20 Archimedes Users, none of them is a IBM User.
> I use both, Macintosh and Archimedes. I *NEED* a Macintosh Disk Readeer for
> the Archimedes!

Actually, I use an Archimedes and a Macintosh and I *still* need a PC disk
reader :-)

> he also writes:
> 
>>  Does anyone know if the high
>>  density drives in the Macs are custom Apple ones (like their 800k drive)
>>  or whether they are industry standard models? 

They are variable speed drives (Sony I believe) which is why writing a Mac
disk reader on ANY machine - not just the Archimedes - is a tricky task.

> If you would know anything about the Mac you'd know that it is able to read 
> and write all PC disk formats.

Incorrect. I have a Mac Plus which does NOT have the enhanced disk controller
chip (Super Wozniak ? I forget the name) - it *cannot* read or write PC disks.
If you have a "SuperDrive" and a model later than a Mac Plus, then you should
be PC-compatible (although why Apple never put the equivalent of the Dayna
DOS Mounter into System 7 is beyond me - messing around with Apple File
Exchange is one big joke). Oh, BTW, I refuse to install System 7 on my Mac -
and I'd warn people against it until they've checked out all the possible
problems (replacing the low-level disk driver on my Rodime hard disk could
be fun ! Plus the fact that Norton Utilities needs upgrading, Pyro! 4 has
to be used as a screen saver and it's dismally slow compared to Pyro! 3 and
so on ad nauseam...).

> The HD Drive used by Apple is a Sony Drive. The only difference to other
> Drives is the ability to eject its Disks automatically and to generate an
> interrupt when a Disk is inserted.

Er, and to vary the rotation speed...

Richard K. Lloyd,       **** This is a MicroVAX II running VAX/VMS V5.4 ****
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