Re: 3.5 for 2c

[dempson@swell.actrix.gen.nz (David Empson)]

In article <9307060324.AA18649@apple.com> 113139@ROO.FIT.EDU writes:
> will the unidisk that is supposed to work on the 2c work on the mac also?
> if so, does the unidisk only come in 800K.

No.  The UniDisk 3.5 does not work on a Macintosh.

I know of five different models of external 3.5" drive which Apple
have released over the years (apart from any the Lisa might have had):

Macintosh external 400k drive
Macintosh external 800k drive
UniDisk 3.5
Apple 3.5 Drive
Apple SuperDrive

The "Macintosh" drives only work on a Macintosh.  They can be
distinguished from the others by their "dull yellow" colour and the
lack of an eject button.


The "UniDisk 3.5" is white.  It supports 800k disks and possibly 400k
(I think there is a bug in the drive which prevents them working in
some cases).  The drive actually has its own microprocessor and
communicates with the computer using the SmartPort protocol.  This
drive is slower than the other 3.5" drives.

The UniDisk 3.5 can be conneted to a IIc (all models apart from the
original), IIc+, IIgs (drive port or controller card) or IIe (with a
controller card).


The "Apple 3.5 Drive" is platinum.  It supports 400k and 800k disks.
The drive has no microprocessor - it relies on the computer to process
the raw data from the disk.

The Apple 3.5 Drive can be used with the IIc+, IIgs (drive port or
controller card), Macintosh (512KE or Plus and later) and IIe (with
controller card).

You can also connect the Apple 3.5 Drive to a PC Transporter, in which
case it can access 720k disks while in "PC mode" and 800k disks while
in "Apple mode" (but very slowly).


The "SuperDrive" is also platinum, and looks exactly like an Apple 3.5
Drive.  Look at the label on the underside to work out which drive it
is.  The SuperDrive supports 400k, 800k, 720k and 1.44MB (high
density) disks.

The SuperDrive works with the Macintosh (IIx or later, or earlier
models which have been modified to support it), and with a IIgs or IIe
which has an Apple 3.5 Disk Controller Card (alias SuperDrive card).

If you connect a SuperDrive to a disk port which doesn't properly
support it, it will act exactly like an Apple 3.5 Drive.


The various controller cards for the IIe and IIgs are:


Apple UniDisk 3.5 Controller Card

This works on a IIe, and not on a IIgs.  It only supports the UniDisk
3.5 drive.


Universal Disk Controller (from Central Point, also known as the Lazer
Disk Controller)

This works on a IIe.  I don't know if it works on a IIgs (but there
wouldn't be much point anyway).  It supports 5.25" drives and the
Apple 3.5 Drive.  Connecting a SuperDrive to this card will make it
act as an Apple 3.5 Drive.  I don't know if this card supports the
UniDisk 3.5.


Apple 3.5 Disk Controller Card (alias "SuperDrive card")

This works on a IIe (possibly enhanced IIe only?) and IIgs.  It
supports the UniDisk 3.5, Apple 3.5 Drive and SuperDrive.  It is the
only interface which supports the SuperDrive accessing 720k and 1.44MB
disks.



The II+ is a difficult question.  You'll obviously need a controller
card, but I don't know if any of them will work on the II+.  I've
never seen the UniDisk 3.5 Controller or Universal Disk Controller.
The SuperDrive controller doesn't mention the II+ anywhere in its
manual.

The PC Transporter will work as a 3.5" disk controller card, if none
of the others will, but only with the Apple 3.5 Drive and not the
UniDisk 3.5.  It is also a rather expensive option if you aren't
interested in running it as a PC.  You do get a RAM disk as well.
--
David Empson
dempson@swell.actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand