Re: 3.5 Unidisk question

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

Robert Stoecker <bigbob@pb.seflin.org> wrote:

> I just purchased a 3.5 Apple Unidisk on apple2.marketplace and it works
> fine.  I already have a 3.5 Unidisk, and this new one is 'just in case'
> the original breaks down.
> 
> Since I purchased both of these used, I have no manuals for them, but I
> pose the following question:   Since the Unidisk comes with a cable 
> terminating in a RSC232 connector, what is the serial jack on the back of
> the drive used for? 

That is _not_ an RS-232 serial connector.  If you tried to plug this
drive into a serial port, or a serial device into the drive, you would
damage the drive.

(For starters, the connectors are different sizes - RS-232 uses a 25 pin
connector, while the UniDisk and other Apple drives have a 19 pin
connector.)

> It's pretty obvious I can't daisy-chain them together

That is exactly what you _can_ do.  Depending on the computer and
controller, you can connect up to four UniDisk 3.5 drives in a daisy
chain.

> and the Apple card (in slot 6) has only one lead.    Is there a 
> connection that can be made to my hard drive by daisy-chaining it to the
> back with appropriate cables and terminators?

Assuming you have a SCSI hard drive, you cannot connect it to same chain
as the UniDisk 3.5 (or vice versa).  Chinook made a hard drive (now sold
by Sequential Systems) which was able to be connected to the floppy
drive port on the Apple IIc.  This drive should also work on the IIgs
drive port, or on a UniDisk 3.5 controller in a IIe.  In all cases, it
must be daisy-chained after the last UniDisk 3.5.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand