How many drives can a GS take?
Greg R. Achenbach
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? 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? What about if I hook up more?
Will they map to other slots? I haven't tried any of this yet. I wanted
to ask the questions before I tried it so I don't end up frying anything.--
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Greg Achenbach gac...@eis.calstate.edu (soon to be ctp.org)
Los Angeles County Outdoor Science School
"Society is like a stew. If you don't keep it stirred up, you get a lot of
scum on top." Edward Abbey
Denis Fafard
> 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? 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? What about if I hook up more?
> Will they map to other slots? I haven't tried any of this yet. I wanted
The maximum recommended is 7 drives. I have never seen a need for
chaining seven in a row, but what the hell, go for it! I've got a GS
with the following: 1-5.25", 2-3.5", /RAM5, /AEROM (ROM drive), and then
/HD1 and /HD2. You get some weird mapping after about 4 or 5 devices,
but it is irrelevant. EG: My 3.5's are 2,1 and 2,2 because I boot from
my Romdrive (AE Ramkeeper). I think the mapping would then go to slot 3.
--
Denis Fafard den...@ersys.edmonton.ab.ca
Edmonton Remote Systems Serving Edmonton/Northern Alberta since 1982
David Empson
Greg R. Achenbach <gac...@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
dem...@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand
Anthony Bean
I personally have 1 each plus 2 AE Ramfactors plus a 40Meg hard drive
with 2 partitions and 315Meg hard drive with 10 partitions.
--
Tim Clark | Customer Service
Northern Telecom | Software Technical Support
Network Application Systems | guest acct: a...@sv3.cci.com
Rochester, New York | t...@csfms.cci.com
David Empson
Jay Krell <jm...@crux4.cit.cornell.edu> wrote:
> What David said, plus, here's a quote from the IIGS Firmware Ref:
>
> "You can attach up to two Disk II drives, two Apple 3.5 drives, and
> two or more UniDisk 3.5 drives to the Apple IIGS disk port, depending
> on IWM output specifications. A maximum of six devices can be connected
> at any one time."
Thanks for the correction, Jay.
> I wasn't aware of the two Apple 3.5 drive limit.
Here are the technical reasons for the limits:
The Apple 3.5 Drive uses the drive select line (as do the 5.25"
drives), which only has two states. I'm not sure if it uses ENABLE2
(pin 9), which is used to enable 5.25" drives; I suspect that it does,
because of the brief blink that is visible on the 5.25" drive select
light whenever a 3.5" drive is enabled.
The reason you can have two drives of both types is that there is an
extra enable line (3.5DISK, pin 4) which is 0 for a 5.25" drive, or 1
for a 3.5" drive.
An interesting point here is that pin 4 is a ground line for the Disk
][, and presumably for the UniDisk 5.25 and other SmartPort devices.
The 3.5DISK output in the IIgshas a series resistor, which should
protect against the output being shorted to ground if there is no Apple
3.5 drive connected.
The Apple 3.5 drive uses this signal (on its daisy-chain connector) to
sense whether a 5.25" drive (or SmartPort drive?) is connected at the
end of the chain and doesn't pass the signal through (the second drive
does this if there are two connected).
The UniDisk 3.5 uses the SmartPort protocol to communicate with the
computer (packets of data sent between two intelligent devices).
Addressing is handled by a 7-bit address byte, so you theoretically
have 127 drives (address 0 is reserved for the host).
The reasons for the drive ordering:
- The Apple 3.5 drive must go first, otherwise it cannot sense the
3.5DISK signal. It doesn't interfere with any signals intended for
SmartPort devices or 5.25" drives.
- SmartPort devices (e.g. UniDisk 3.5) must go next, so that they can
disable 5.25" drives (via the ENABLE2 signal) when a SmartPort access
occurs.
- 5.25" drives go last.
References:
IIgs Firmware Reference
IIgs Hardware Reference (2nd edition)
Inside Macintosh Volume III
IIc Technical Reference (1st edition, possibly 2nd as well)
Jay Krell
"You can attach up to two Disk II drives, two Apple 3.5 drives, and
two or more UniDisk 3.5 drives to the Apple IIGS disk port, depending
on IWM output specifications. A maximum of six devices can be connected
at any one time."
There is a picture of the order the devices must be connected
(Apple 3.5, UniDisk 3.5, 5.25) and there are two pages
of example slot/drive mappings.
I wasn't aware of the two Apple 3.5 drive limit.
-- Jay, j.k...@cornell.edu