Re: Zip disk on SCSI

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

Louis Cornelio <cornelio@crl2.crl.com> wrote:

> The iomega zip drive is set to SCSI ID5 with the termination switch on.
> I am lucky to have any SCSI card! :) How exactly would the apple hi-speed
> need to be "modified"?

If the ZIP drive is the only device connected to the computer, and the
Apple HS SCSI card has not been modified as described, then no device is
providing termination power.  This is required to make the termination
work properly.  Without termination power you will almost always get
unreliable communication over the bus.

The RamFast does provide termination power, and either Apple card can be
modified to do so by adding a diode in the correct location (I don't
have the details handy - Nathan's FAQ probably points to a source).

It is also possible for drives to supply termination power.  If more
than one device does this, the one with the highest voltage output will
"win" and end up supplying termination power for both ends of the bus.
(This is perfectly safe.)

Most of my external hard drives supply termination power, so I've never
bothered to modify my Apple SCSI cards.  (I'm not all that happy with
the idea of the SCSI card supplying it, because it can cause the card to
draw more current from the +5V rail than the rated maximum for ALL cards
together.)

> the system tools will NOT particion the Zip drive.

I'm pretty sure Advanced Disk Utilities worked for me.  I know I used
Chinook SCSI Utilities to partition a disk, but I'm not sure if I also
tried A.D.U.  With C.S.U. I got three 32MB partitions on the ZIP disk,
and they worked fine.

A.D.U. should treat the ZIP drive just like any other removable hard
drive (e.g. a SyQuest), so there is no software reason for it not
working.

Try it again after checking that you have correct termination power.

> Neither will the HD setup tools on the mac

They only support Apple drives (and a small selection of third-party
drives with recent versions of Drive Setup).

> or the iomega tools that come w/ the drive.

Iomega doesn't seem to consider partitioning a ZIP disk to be useful, so
they didn't include this capability in their software.  I've never used
a Jaz, so I don't know if partitioning is provided for them.

It is certainly possible to partition a ZIP disk on a Mac, e.g. using
third-party drivers (FWB's HDT, for example).  There may be technical
reasons why other drivers should be avoided (this is a rumoured
potential cause of the "click of death", for example), so I'd hesitate
to recommend this until there is more evidence either way.  At the very
least, using non-Iomega drivers will result in loss of features such as
password protection.

> MEanwhile the oddity of getting 2 "not recognized" msgs is solved -- the
> GS seems to read the zip drive w/ 2 tiny "partions" built in of 5k and 200k,
> so I initialized those & now they show up. But I wish there was a way to
> chencge their size to something useful!

One of those will be the SCSI Manager 4.3 driver, which the Apple driver
on the IIgs doesn't recognise, so it is treated as a foreign file
system.  (Older Mac driver partitions are ignored by Apple's SCSI
drivers on the IIgs.)

I'm not sure what the other one is - probably something Iomega-specific.

> Withe the SCSI card in slot 2 & that set to your card, I didn't think the
> modem would still work, but it does.

What communications software are you using?  Some of them bypass the
firmware and access the serial hardware directly.  Since the SCC chip is
outside the slot address space, this does not interfere with the SCSI
card.

> Th weird thing is I thought I'd have to sacrifice either printer or modem,
> so I had previously set slot one to modem & connected the modem there
> rather than my IW. The modem wouldn't work.

Hm, not sure why - I've done this, and it works fine as long as the
software can handle using slot 1 instead of 2.  You might need to fiddle
with some of the other control panel settings so they match the slot 2
defaults.

You didn't have AppleTalk enabled, by any chance?  That might cause
problems.

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