[net.micro.apple] Unidisk

ralphw@ius2.cs.cmu.edu (Ralph Hyre) (12/13/85)

In article <2236@reed.UUCP> kamath@reed.UUCP (Sean Kamath) writes:
[about new Apple // products]
>	There's lots of magic in the UniDisk connection, too.  It's really
>more than that.  Apple's documentation call it CBUS--it's a non-standard
>high-speed serial connection for "intelligent" paripherals.

Why not use SCSI or the already existing Mac interface? (especially for
new disk technology where you don't need to be compatible with the old
controller)  If Apple sold a SCSI-compatible 3 1/2" disk then I could have
a system with ONE disk controller.  Mac-compatibilty would conserve Apple's
hardware development resources, and it also gives you more compatibility
between machines.  I guess the NIH (Not Invented Here) symdrome has been
carried over from Apple's old product division structure as well.

>become intelligent when they have a microprocessor and software in them.
>Subsciber Tom Vier has discovered that inside each UniDisk 3.5 there's a
>6502 microprocessor, ROM, RAM, and one of Apple's IWM chips.

You're kidding!  That's why they retail for $499 (although mail-order
houses seem to have them for around $250 (w/controller)).  Maybe I should
add a terminal to my Unidisk and use it for my second computer :-)

Why did Apple do this?  Most people attach their drives to one machine.
If the drive's 'intelligent', will it queue up read requests and have a chance
at running a real multasking OS for the machine?  (The disk was always the
bottleneck before.)  I'm worried because I remember those 'smart' Commodore
disk drives.  What implications will this have for copy protection?

Where can a get an dumb, high-density (>720K) 3.5" drive for my Apple that
I can use under ProDOS and CP/M?  I'd even consider building a Mac-compatible
controller or writing drivers if someone has a schematic.



--
					- Ralph W. Hyre, Jr.

Internet: ralphw@c.cs.cmu.edu (cmu-cs-c.arpa)	Usenet: ralphw@mit-eddie.uucp
Fido: Ralph Hyre at Net 129, Node 0 (Pitt-Bull) Phone: (412)578-2847,578-3275

-- 
					- Ralph W. Hyre, Jr.

Internet: ralphw@c.cs.cmu.edu (cmu-cs-c.arpa)	Usenet: ralphw@mit-eddie.uucp
Fido: Ralph Hyre at Net 129, Node 0 (Pitt-Bull) Phone: (412)578-2847,578-3275