Re: How many drives can a GS take?

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

In article <2pu4pg$b5q@eis.calstate.edu>,
Greg R. Achenbach <gachenb@eis.calstate.edu> wrote:
> The subject line pretty much says it.  I have a GS with one 5.25 drive 
> and two 3.5's.  I know I could put another 5.25 on, but have no need to.  
> How many 3.5's can I have?

There are several different limits which are imposed:

You are limited to two 5.25" drives connected to each controller
(whether it is a card in a slot, or a built-in disk port).  Note that
the IIc's internal drive counts as one, so you can only connect one
additional 5.25" drive to a IIc.

You are also limited to two Apple 3.5 Drives or SuperDrives connected
to each controller (two of either type, or one of each type).  The
IIc+'s internal 3.5" drive counts as one drive of this type.  The 3.5"
drives are counted independently from the 5.25" drives.

In theory, you can connect up to 127 UniDisk 3.5 Drives to any one
controller, regardless of how many Apple 3.5 Drives or 5.25" drives
you have connected.  In practise, you are limited by the power supply
and signal strength.

I think the IIgs and IIc disk ports are limited to four drives (any
mixture of types, and don't forget to count the IIc's internal drive).
The Apple II 3.5 Disk Controller Card appears to be limited to two
drives (I've never tried it with more than two).


For the IIgs and IIc disk ports, 5.25" drives and 3.5" drives are
handled independently.  5.25" drives appear to be in slot 6, and 3.5"
drives appear to be in slot 5.

You start to run into problems if you have more than two 3.5" drives,
or two 3.5" drives and the IIgs RAM disk (/RAM5) or ROM disk (/ROM5).

ProDOS was originally designed to support no more than two devices per
slot.  ProDOS-8 1.2 relaxed this slightly: a card in slot 5 can have
four devices, with the last two being re-mapped to slot 2.  This only
works if slot 2 doesn't contain a disk controller card.

ProDOS-8 2.0 relaxed this further: if the disk controller supports the
SmartPort protocol (as in the case of the IIgs and IIc disk ports),
any devices beyond the first two will be remapped to any unused slot
(one that doesn't have a disk controller - there is no problem
remapping a device to a slot which contains a serial or parallel card,
for example).

On to your specific questions:

> I have a /RAM5 set up in the control panel.  This ends up being Slot
> 5, DRive 1 since I have it sut up to boot from.  My first 3.5 then
> ends up as S5, D2, and the second one as S2, D1.  Can I hook up
> another 3.5 and have a S2, D2?

If both your 3.5" drives are Apple 3.5 Drives, then you cannot hook up
a third drive of this type (nor could you hook up a SuperDrive).  You
could use a UniDisk 3.5, which would then appear as S2,D2.  If you
removed your 5.25" drive and connected a second UniDisk 3.5, and you
were using ProDOS-8 2.0 or later, it would be remapped to some other
unused slot (e.g. slot 1).  You couldn't connect any more than this
without exceeding the four drive limit.

Another option is to get an Apple II 3.5 Disk Controller card (a.k.a.
"SuperDrive card").  You could then hook up a further two Apple 3.5
Drives or SuperDrives to this card.

A far better and probably cheaper option would be to get a SCSI card
and a hard drive.  It is far more convenient to use a single large and
fast disk drive rather than several relatively small and slow floppy
drives.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand