Apple II SCSI card

From: Paul R. Santa-Maria <>
Date: Tue Oct 30 13:27:49 2001

Rich Beaudry:

You have an Apple II Rev C SCSI card, not the High Speed card.

Below is a comp.sys.apple2 post with more details about the card,
including some limitations.

I have one in my IIgs. I also have the original manual and software, but
the Chinook SCSI Utilities (CSU) software is better (see below). I can
provide you with copies of this stuff. I can point you to online sources
of disk images if you can handle them.

For others with Rev A or Rev B versions, I can make Rev C EPROMs.

Paul R. Santa-Maria
Monroe, Michigan USA

From: David Empson (
Subject: Re: Apple II SCSI Card rev C - Latest Revision?
Newsgroups: comp.sys.apple2
Date: 1998/09/11

Brian <> wrote:

> I just acquired an 1996 Apple II SCSI Card revision C, for my ROM 1
> IIgs.

I think you'll find that date was 1986, not 96. :-)

> Is "C" the last revision of this card?

There is only one version of the physical card. "Revision C" refers to
the firmware version. The ROM should be labelled "341-0437-A" if it is
revision C.

Revision C is the last release of the firwmare for this card.

> Are there any problems I should be aware of?

Many. Where should I start?

1. The card is not terminated.

If you are connecting more than one device, you must place a
pass-through terminator between the card and the first device (or
internal termination in the first device), as well as after the last
device on the chain.

If you are connecting a single device, it should have internal
termination or a piggy-back terminator.

2. The card does not supply termination power.

There is a single diode modification that can rectify this. Another
option (my preference) is to make sure that at least one of the
connected devices is able to supply termination power.

3. The firmware is limited to seven logical partitions.

These partitions may be spread over as many as 7 SCSI devices connected
to the card. Under ProDOS-8, this gives a practical limit of 224 MB
accessible over all volumes. Note that you need to be running ProDOS-8
2.0.1 or later to be able to access more than 4 partitions, and this
requires at least an enhanced IIe. Under earlier ProDOS versions, you
can only access 3 or 4 partitions if the card is in slot 5.

The seven partition limit does not apply under GS/OS, which uses its own

4. The firmware doesn't fully support removable hard drives, including
devices like ZIP drives.

The problem is that if you switch disks, the firwmare does not update
its saved copy of the partition table. This can easily result in
corruption of the new disk if it is not partitioned EXACTLY the same as
the previous one (right down to the starting block number and number of
blocks in each partition).

This problem doesn't affect GS/OS, and you can work around it under
ProDOS-8 by rebooting if you need to change disks.

Note that if you boot via GS/OS and then get into ProDOS-8, quitting to
GS/OS and relaunching ProDOS-8 might not be sufficient to reinitialize
the firmware (I haven't investigated this).

5. The firwmare only supports SCSI hard disks and CD-ROM drives. CD
Audio operations are only supported with Apple's original CDSC, CDSC+
and CD-150.

This isn't likely to be a major issue.

6. The card is slow.

The Apple High-Speed (DMA) SCSI card is a lot faster (as long as DMA can
be used), and the RamFast is even better.

7. The partitioning software that comes with it is pretty limited.

If you didn't get the disk, this isn't an issue. A much nicer 8-bit
alternative is Chinook SCSI Utilities, which is now freeware. (I don't
know of a source for it off-hand.)

You can also use Advanced Disk Utility under GS/OS.

David Empson
Snail mail: P.O. Box 27-103, Wellington, New Zealand
Received on Tue Oct 30 2001 - 13:27:49 GMT

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