Using a Zip drive ona Mac Plus



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Mad With Macintosh



Using A Zip Drive On A Mac Plus


Date: Mon, 24 Aug 1998 03:18:29 +0000

Subject: Re: zip drive on plus

From: "Michael A. Peters" <>



These are my experiences with a Zip Drive and a Plus-


1) A zip drive makes a very stable HD for a Plus, I know people who have been using them as a bootable HD for YEARS (yes, YEARS) with only occasional problems that Norton has fixed (BTW, I've had to use Norton on my new G3 HD

Once, so I don't see this as a zip problem)


2) You need to use an Iomega Driver older than version 5.x. Otherwise you get a sad Mac when booting. You also can NOT allow your zip disk to be loaded in a machine with a 5.x driver, 'cause part of the driver will update itself, and give a sad Mac when booting with a zip disc in the drive.


3) The best thing to do, in my opinion, is get a small (cheap) SCSI HD for your plus, put SSW on it, including your Iomega driver. I use a 30MB myself. Boot off of the HD with no zip disc in the zip drive, insert zip disc after booting. The zip disk can now be used as a non-boot volume, which also makes backing up files easier onto a second zip disc. (hint: only keep SSW on your boot HD- this leaves plenty of room for transferring backups from zip to HD to back-up zip, less disk swapping)


This will work regardless of whether or not your zip driver has been polluted with a 5.x system. Note- if your driver has been polluted (like the one on my Plus) you MUST boot with no zip disk in the zip drive. That's why I say it's best to boot from a small HD, because you don't have to worry about what computer your Zip Disk is used in.


If you need it, I can send you a copy of the 4.2 driver and tools. Please note that my particular 4.2 extension is polluted, and can not be used to make a boot disk. I do know a friend who has been more careful with his driver, and his can be used (and is used) to boot a Plus from a zip, if you really want to take that route.


Note- this driver update thing was a VERY bad feature on Iomega's part! I know of one case where an individual with a Performa had the 4.2 driver and zip tools. he used his zip disc in a Mac with a 5.1 driver, went home and used it in his Performa. The next time he booted, he put his zip disc in the Performa before booting, had no problems- until he tried to use his zip tools! he got a nasty message saying he couldn't use his tools 'cause they were too old for his driver! As it turns out, he could only use his tools if he boots with no zip disc in the drive. Because Iomega thought they were so smart, he had to upgrade his Iomega stuff to consistently use his drive the way had been using it no problem before.


Download the Zip Driver

another page devoted to this subject


Recently I got bitten by the bug and once again am a zealot for the plus- For some odd reason, I've decided to do whatever I can to help make these wonderful machines as useful as possible.

Quick Instructions

  1. Create a SSW 6.0.8 boot disk with the Iomega 4.2 driver installed.
  2. With Plus powered off, Zip Drive powered off, attach the Zip Drive to the SCSI chain. Make sure the zip drive termination is set to "on" if it is the LAST device in the chain- set to "off" if other devices are AFTER zip drive.
  3. Power on all items on the SCSI chain.
  4. Power on Plus, booting from the floppy. Your Zip Disk should NOT be inserted in the drive yet.
  5. Insert the Zip Disk- it *should* mount.
  6. Select "Erase Disk" from the Special menu. This will properly format the disk for use with a Plus.
  7. Install System Software on to the Zip Disk.
  8. Place the Iomega 4.2 Driver into the System Folder (SSW 6.0.8) or the Extensions Folder (SSW 7.x).
  9. You *should* now have a bootable Iomega Zip Disk!

NOTE: The above procedure WILL NOT work if your zip disk is PC format- Iomega Tools are required if you have a PC format Zip Disk, and Iomega Tools does not work on a Plus.

IMPORTANT UPDATE! Iomega just released a new 250MB Iomega Zip Drive. I do not know if this drive will work with the Macintosh Plus. I supspect that if it does- the 250MB Zip Disks would not work, for the simple reason that I do not think the Iomega 4.2 Driver will work with these disks. I'll post more info on this new drive and the Plus when I know more.

Nitty Gritty Information

There are numerous rumors related to getting a zip drive working with a Plus. I will be looking into this issue and trying to resolve it- trying as best as I can to seperate fact from fiction. Results will be posted here.

The Rumors

The Iomega Zip Drive does not work with the Plus
False- At least with some Plus's, the Iomega Zip Drive works with the 4.2 driver/tools and I've heard with the 4.3 also.
The Iomega Zip Drive only works with a Macintosh Plus if you have ROM version 3 in the Plus
Don't know, really don't think so. My Plus does have the version 3 ROM chip in it- I hope to soon be able to test the version 1 and version 2 ROM chips with the 4.2 driver and see if they work. For the record, I have NEVER seen a Plus where a zip drive didn't work- so either I've only seen ROM v3 Plus's tried, or the rumor is false. I will find out.
The zip disk can not be used as a boot disk for a Plus.
False. I currently boot both a SSW 7.1 Zip Disk and a SSW 6.08 Zip Disk no problem!
The zip disk does not work with System 6.08
False. The Zip Drive works beautifully on a 1MB Plus running SSW 6.0.8, with *possible* ROM version exceptions.
The 4.x driver will auto-update itself if it is in the presence of a 5.x driver
True, sort of. The "Iomega Driver" that sits in the extensions folder (system folder for SSW 6) doesn't change- but any zip disk inserted while a 5.x driver was loaded at boot will have a 5.x driver on the Zip Disk itself. Also, if a zip disk has a 5.x driver on the media itself- if the disk is in the drive at boot time- the 5.x info off of the zip disk will take over. Really a bad feature- I'm working a hack that will re-write 4.2 driver information onto the zip disk media itself. This hack would, of course, be totally unsupported by Iomega (but then, so is the Zip Drive on a Plus!)
The Iomega 4.2 driver is hard to find.
It use to be at titled zipmac42.sea.hqx. Now, it is available here.

Auto Update Quirk

The Iomega drivers like to update themselves to a newer version, sad but true, which is what I think is actually responsible for the ugly rumors. When you try to boot from a zip disk that has been "updated" you either get a sad mac (SSW 6.0.8) or it rejects the disk (SSW 7.1).

This is how it works- at least, I think! (still doing some experiments) To explain this as easilt as possible- I have to make a distinction. There are two types of Iomega Drivers: Iomega Device Driver and Iomega Media Driver.


Iomega Device Driver
This is what sits in your extensions folder (system folder SSW 6). This tells the OS, more or less, how to best talk with the Iomega Drive. This loads at start-up- when the system boots.
Iomega Media Driver
This is information that sits on the Zip Disk itself, in it's own little partition.


When the system boots, it loads the Iomega Device Driver. While loading the Iomega Device Driver, it checks the version of the Iomega Media Driver. If a newer version of Iomega Media Driver exists on the media- it loads newer information, at boot time, than the Iomega Device Driver knows about. Thus, if you have a 4.2 Iomega Device Driver in your extensions folder and at boot time, there is a zip disk with Iomega Media Driver 5.x in the zip drive- your Mac *thinks* that Iomega Device Driver 5.x was loaded. This is bad- because it means that Zip Tools 4.2.1 won't work! The Iomega Solution is to update the Iomega Software on your Mac (fat bit of good that does for Plus owners- but the Plus technically isn't a supported computer)

During system boot OR AFTER the system has booted- any zip disk with an Iomega Media Driver OLDER THAN the Iomega Device Driver will get new Iomega Media Driver information automagically written to it. Bummer.

How to *fix* your zip disk to work with a Plus

There is currently only one easy option I know of available to people with Zip Disks that contain 5.x Iomega Media Drivers on them.

On a newer than Plus mac, boot with the Iomega Device Driver 4.2 in your system folder, no zip disk in zip drive. Once booted, back up all the info on the zip disk. Use Zip Tools 4.2.1 to reformat the zip disk. Re-install the data- you *should* be good to go.

Unfortunately, you can't use Zip Tools 4.2 from a Plus to give a disk a 4.2 driver with the fresh re-format option. The problem is that Zip Tools will tell you it requires a "MacSE or newer running System 7".

Yes, I tried "lying" to the software, using the extension/control panel set called "Wish I were..." but the Zip Tools wouldn't buy it! Too bad.

What you CAN do on a Plus is boot from a SSW 6.0.8 floppy w/ appropriate 4.2 driver in system folder, no zip disk in zip drive. Insert zip disk- it will mount. Backup Data- and use "Erase Disk" from the Special menu. The zip disk will erase, and the 4.2 driver information will be loaded onto the disk. You are then good to go.

NOTE The hack I was working on won't work. Basically- I was going to mimick an application called pdisk, compiling only the necessary portion (with slight modification) for the Plus. With pdisk- you can see all the partitions on a zip disk, and remove any partition. My plan was to remove the partition containing the bad media driver information, and hope that the 4.2 device driver would automagically put 4.2 media driver onto the zip disk- much the same way as a 5.x device driver automagically puts 5.x media driver onto a zip disk w/o damaging files.

On a G3- it sort of works, but not really. The G3, with the 4.2 driver, will still recognize AND mount a zip disk that has had the media driver removed. However, it won't put a new driver in place- it just leaves it well enough alone. On a Plus, it refuses to mount a zip disk without a media driver, period, not even if the zip disk is not the boot disk.

Unfortunately, I can't write anything that will put the 4.2 drivers onto the media- as I would be opening myself up to lawsuit from Iomega. That's why I was hoping the Iomega Device Driver would kindly do it for me. Oh well.

Iomega Zip Disk Partition Map

For those of you interested- this links to typical pdisk output

Iomega Version 6

Iomega now has version 6 of their software available- they call it ioware 1.0, but it's really just the same old but newer version. I have never tried it- don't know if a zip disk w/ iomega media driver 6.x will even mount in a Plus for erasing. I'll find out soon enough, I guess.



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