Jazz Drives and OSR 5

This guide covers the configuration and use of the 1Gb and 2Gb Iomega Jaz drives under SCO OpenServer.

1. Introduction

The Iomega Jaz drive is a removable-media disk drive whose disks have a capacity of 1 or 2 Gigabytes. Unlike the Zip drive, the Jaz is only available as a SCSI device (internal or external), so a SCSI interface card and driver are required to use these drives.

2. Jaz Hardware

Jaz drives are SCSI devices and are available as an external drive with a 50-pin SCSI-2 self-terminating interface or an internal 3-1/2 format drive with a 50-pin header interface.

Both the internal and external devices are available in either 1 or 2 Gigabyte capacity, so there are four different Jaz drives available.

While not having the same capacity the Iomega Zip drive can also be used with SCO OpenServer - Note however only the SCSI version is supported - NOT the parallel port version. Installation and use are the same.

2.1 The Jaz "Disks"

Jaz disks are a cartridge-style removable media containing a stack of three 3.5" platters. From here out, I'll be using the terms "cartridge" and "disk" interchangeably to mean the Jaz media.

The 1Gb and 2Gb cartridges appear similar, but there is actually a subtle difference in their shape which prevents a 2Gb cartridge from being fully inserted into a 1Gb drive. Obviously, this means that you can't use a 2Gb cartridge in a 1Gb drive.

The 2-Gb capacity Jaz drives can read, write, and format both 2-Gb and 1-Gb Jaz cartridges.

2.2 SCSI Host Adapter

Iomega markets a SCSI host adapter under the name Jaz Jet. However, there are at least two different SCSI chipsets that are used. You're better off getting a card that you know your SCO OpenServer distribution will support

Personally, I don't like surprises, so if I were going to buy an adapter card, I would get a name-brand card with a 50-pin connector, so that I knew that what I was getting was supported.

If you're using an Ultra-Wide SCSI card with a 68-pin connector, you'll need to get an adapter or another cable. The adapters do indeed work just fine with the Jaz drive, but can be rather pricey, so if you're buying a SCSI card primarily for the purpose of connecting the Jaz drive, you're better off picking up a card with a 50pin connector on it.

The AHA-2940 is an excellent choice as well, and it has been supported for for a long time, it's just more expensive.

As always, be sure that your SCO OpenServer distribution supports a particular card EXPLICITLY before making a purchase. Many manufacturers, like Adaptec, have cards with numbers and letters similar to each other that are actually completely different chipsets, and therefore use completely different drivers.

3. Identifying the Jaz Drive

3.1 During Power-On Test

With a SCSI controller installed, when the machine is powered up or reset the SCSI controller will scan the SCSI bus looking for attached devices before booting the operating system.

If your SCSI card is correctly installed, and your Jaz drive is attached and powered on, you should see the drive listed as something like "Iomega Jaz 1GB" or "Iomega Jaz 2GB" during this time.

If the drive doesn't show up, there's no sense booting SCO OpenServer. Power down the PC and Jaz drive, and check everything again. In particular, unplug the cables and make sure none of the the pins are bent, then replug them and ensure they are completely seated against the connector. If you have multiple SCSI devices, make sure they all have different ID numbers, and that the last device in the SCSI chain is terminated.

When the drive shows up in the power-on test, you're half way home.

3.2 During Boot

When SCO OpenServer boots the SCSI driver should display information about your SCSI adapter.

Boot messages will vary depending on your driver and adapter, and are logged to the /usr/adm/messages file as well as appearing on the screen during boot. You can also see the current configuation from the command prompt with the hwconfig command.

3.3 Configuring OpenServer

A Jaz disk looks the same as a hard drive to SCO OpenServer, so for those of you familiar with the SCO OpenServer disk management tools, none of the following will be a surprise.

You need to tell OpenServer that the drive is present. Log in as root and run the command:

mkdev hd

If you need to know the host adapter then look in /etc/default/scsihas.
You can also check www.sco.com for any updated or new drivers.

Answer 'Y'es to Re-link the Kernel, then Re-Boot the System

Re-run mkdev hd with the same options as earlier, and you will be taken into fdisk (just pick 'Use Entire Disk for Unix'), and divvy in turn.

While in divvy re-name the 1st division to something meaningfull e.g. jaz, it will make life easier later on and set the 'Create Filesystem' option to yes.

Note: Make a note of the device node e.g. /dev/dsk/3s0, or the shorter version /dev/hd30, as you will need it later.

As the Jaz disk can be used as a filesystem it is advisable to add filesystem support at this time. Run (still as root)

mkdev fs
  • Add a new filesystem
  • Device name - /dev entry e.g. /dev/hd30
  • Directory Name - Again something sensible e.g. /jaz
  • As the Jaz disks are removable, generally you will not want to mount it when starting up - pick 'Never mount /dev/xxx'.
    This can be changed later by editing /etc/default/filesys.
  • Answer 'Y'es to allow users to mount this filesystem.
  • From now on this guide will assume that the device entry is /dev/hd30, and that the initial filesystem was named 'jaz' with a mount point of /jaz.

    4. Using a Jaz Disk

    Jaz drives can be used in two modes:

    4.1 Filesystem

    SCO OpenServer-Native Jaz disks allow files to be stored with standard Unix permissions and case-sensitive filenames. The only drawback to SCO OpenServer-Native disks is that they can no longer be used on DOS/Windows machines.

    You can mount the disk by typing

    mount /jaz

    Treat the Jaz drive as you would a hard disk, all the usuall commands will work.

    While the disk is mounted, you will not be able to eject it.

    When you are done with the disk, you can unmount it with the command:

    umount /jaz

    Once unmounted, you can press the button on the front of the drive to eject the cartridge.

    4.2 Creating a Filesysem

    The earlier step as created a filesystem on one of your Jaz cartridges. You should at least once, initialise all the cartridges you will use.

  • fdisk -f /dev/rhd30 - Use Entire Disk for Unix
  • Creating a filesysem
    mkfs /dev/rhd30 size:2000 1 80 size Can be: 1Gb Jaz 2091008
    1Gb Jaz ??????
  • 4.3 Running fsck on Jaz Disks

    Like your other disk drives, once a SCO OpenServer Jaz disk has been mounted and the system is closed down incorrectly, the system will mark the disk as "dirty". When this happens, you'll get a message like:

    Unable to mount, /dev/hd30.

    Once you see this message, it's a good idea to go ahead and check the disk. The disk must be unmounted in order to check it. Unfortunately, you only get the "dirty" message when you mount it, so you can either check the disk when you're done using it, or unmount it, check it, then re-mount it. Use the following command to check the disk:

    fsck /dev/hd30

    4.4 Raw Device

    It is possible to copy onto a Unix filesystem, however for a backup device it is easier to treat the Jaz cartridge as a raw device.

    You can backup onto the device as per:

    tar cvf /dev/jaz filename filename ..

    4.5 Configuring BackupEdge

    Use the following settings:

    4.6 DOS Formatted Disks

    Jaz disks come pre-formatted from Iomega with a single partition using the DOS FAT16 file system. The single partition is usually the 4th disk partition (for Mac compatibility - the Mac requires data to be on the 4th partition, but the PC doesn't care which partition data is on).

    SCO OpenServer is perfectly happy reading and writing a FAT16 file system, so you can use the disk as is.

    Example Usage:

    4.7 The Jaz "tools" Disk

    With some Jaz drives, the software to run the drive is supplied on a Jaz cartridge instead of on CD-ROM. The "problem" with these disks is that software-controlled write protection is enabled on the disk, so that the user can't wipe the disk until after the tools are installed at least once.

    There are several ways you can reclaim the Jaz tools disk:

    If you have access to one of the password protection removal programs, all you need is the password that Iomega uses, and it is:


    Note that capitalization is important.

    6. Booting from a Jaz Cartridge

    Under Investigation

    7. Further Information

    This HOWTO is based on the Linux HowTo created by Herb DaSilva.
    The Linux version can be found at http://www.ultranet.com/~hsd/HOWTO/

    Related Web Sites

    Jaztools - Linux tools for Jaz Drives http://www.willmot.com/jaztool/

    Iomega Support Notes - http://www.iomega.com/support/documents/10016.html

    Comments and suggestions always welcome - tom@tkrh.demon.co.uk