Iomega Zip Drives


Iomega zip was a  very promising removable disk device. It sold millions of devices into the decade 1990-2000. Backup purposes was the main reason for buying such a device.

In nowadays it is still used for old machines for backing up the hdd contents. Parallel, scsi connection is very reliable!


Types of Interfaces  Types of Iomega Drives
DOS Mode   Windows 3.1/3.11
  Loading the ZIP drive    
  Specifying a Drive letter   Windows 9.x
  Speeding up Transfer speed     Specifying a drive letter 
  Optimizing Memory usage   Loading a ZIP Drive with a Boot Disk
  Tools  Troubleshooting

Types of Interfaces

There are several types of Iomega Drives that you might use. The biggest difference is the way they are connected to your computer.
  • Parallel Port ZIP 100 Drives:

  •       These external drives are easily moved from one computer to another. Since they are connected to the parallel port which almost every computer has, you can move it easily from one computer to another, making it easy to transport large amounts of data from one computer to another.

          The biggest disadvantage is that it has the slowest transfer rate of the ZIP Drives. Depending on the driver you use and the settings that can be used with a particular computer, you can optimize it to about 3 times its default speed.

  • SCSI ZIP 100 Drives:

  •       Similar to the Parallel Port drive, these can transfer data much faster than the parallel port drive, about 3 times as fast. In most other aspects it is the same.

          The biggest disadvantage is that it can only connect to computer that have an SCSI card installed.

  • ZIP 100 Plus Drives:

  •       This drive has the best of both worlds. It can connect to either a parallel port or an SCSI port. So you can have the speed of the SCSI (when connected to an SCSI interface), and the universal compatibility of a parallel drive.
  • IDE/ATAPI ZIP 100 Drives:

  •       These internal drives connect to an IDE channel and operate much the same as a ATAPI CDROM. If your BIOS accommodates it, it can be set up as your A Drive, in which case you can make it bootable. Otherwise it can be loaded in the same manner as the parallel and SCSI drives, except that it is faster and it is "Internal".
  • USB ZIP 100 Drives:

  •       This latest addition to the ZIP family has the portability of the external drive and the speed of the IDE/ATAPI drive. But it can only be used on a computer with a working USB connector. This limits its use to only the later computers using Windows 95c and up, or equivalent other operating systems.

    Types of Iomega Drives

  • ZIP 100 Drives:

  •       Virtually all of the above drives are compatible with 100Mb ZIP disks.
  • JAZZ Drives:

  •       JAZZ Drives have disk capacities of 1gb. The JAZZ disk cannot be used in ZIP drives and ZIP disk cannot be used in JAZZ. The connection methods are pretty much the same.
  • ZIP 250 Drives:

  •       These later version of the ZIP drives are compatible with 100Mb ZIP disks. But they can also use 250mb Iomega Disks. The connection methods are the same as ZIP 100 drives.

    DOS Installations:

    DOS Setup:
          If you have an Iomega Installation CD, you should find SCSI drive utilities. This contains the drivers for DOS loading of the drive. These will probably be in a self extracting file named IOMEGA.EXE. On the CDROM that came with my drive, this was in \english\dosstuff\.

    By default these will be expanded into the directory you are in when you run that IOMEGA.EXE file.

    Loading the drive:

    To make the ZIP drive operational, if the drivers are in c:\iomega\, type:
    cd c:\iomega
    and that's it.
    Specifying a drive letter:
    You can specify what drive letter will be assigned by typing:
    guest letter=y
    Y is the highest letter you can get to work in DOS. You must add the line:
    to the c:\config.sys file for Windows 95a and earlier. This also may be necessary with Windows 95b and later. The lastdrive= must be as high as the highest letter you plan to use. The guest letter= can only be a letter not already used or reserved.

    Optimizing the Transfer Speed:

    Running the OPTPPM1.EXE will test the parallel port connection for the fasted transfer rate that can be used. The file and settings will be added to the GUEST.INI file. The old GUEST.INI is saved as OPTPPM1.OLD incase you need the original settings back.

    In the line
    the file= may be nibble.ilm or byte.ilm if the ASPIPPM1.SYS is used. If ASPIPPM2.SYS is used, the file= may be nibble2.ilm or byte2.ilm. the speed= can be number 1 to 10.

    If byte.ilm or byte2.ilm is used and the system does not work correctly, replace it with nibble2.ilm or nibble.ilm as appropriate.

    Also reduce the speed= until it works properly.

    These settings can be used in the CONFIG.SYS as described below in Optimizing Memory usage.

    Optimizing Memory usage:
          You can load the drivers with the "GUEST.EXE". Using the "GUEST.INI" as a guide, this program tests for the correct driver, then loads that driver in memory along with the "GUEST.EXE". This can use a lot of conventional memory. And the method does not allow it to be loaded into "high memory". You can specify the correct driver and load it into high memory as a separate function. This allows both the driver and Guest to be loaded "HIGH" in most installation, to free up "Conventional Memory".

          To do this you must first determine which driver is used. To do this, with the ZIP drive loaded by GUEST.EXE, at the DOS prompt, type:

    mem /p /c
    Among the drivers you see loaded you should see one of the following:
    The one you see is the correct one for your drive and computer.

    Next, edit the GUEST.INI file. Find the line with that driver. Copy that line and paste it into the CONFIG.SYS file. Then modify the line for loading.
    What you import may be:
    aspi=aspippm1.sys /info file=nibble.ilm speed= 1
    change this to:
    devicehigh=c:\iomega\aspippm1.sys /info file=nibble.ilm speed= 1 /info

    The /info displays the setting when the driver loads. This optional tag can help you see if the device loaded properly.

    Now you must RENAME or DISABLE the "GUEST.INI". I change the name to GUEST.INN.

    When you boot the computer, the driver will be loaded in HIGH MEMORY. The GUEST.EXE will be executed the same as it was before. You can add LH before it to load it to HIGH MEMORY as well. The whole loading process goes faster as it does not have to test for the correct driver.

    TIP: When you are loading a ZIP drive along with other devices such as a CDROM drive, the sequence they are loaded in can determine whether they are both able to be loaded into High Memory. If GUEST.EXE is loading in Conventional Memory and MSCDEX.EXE is loading in High Memory, loading Guest first may result in both being loaded High. When drivers are loaded, they need more memory while loading than they use once installed. If you load a driver that has a "Low Overhead" (using no more than it needs) after one that has a "High Overhead", there will be enough available memory while the driver is loading.

          If MSCDEX.EXE needs 20kb but has an overhead of 25kb, and Guest needs 20kb but has an overhead of 40kb, if you loaded GUEST.EXE first in 50kb of memory, there would be 30kb left for MSCDEX.EXE which only needs 25kb to load. If MSCDEX.EXE is loaded first, you still have 30kb free. But guest needs 40kb to load. So it will load Low.

    Iomega DOS tools:
    SCSIUTIL.EXE is both a command line utility and a Graphic User Interface (GUI) utility.
  • You can use this to Lock and Unlock the ZIP disk to prevent it from being ejected.

  • It can also test the disk.

  • It can format the disk

  • It can Password Protect a disk

  • It can Write protect a disk
  • Type SCSIUTIL /? for the commands, or.
    SCSIUTIL to run the GUI.


    Windows 3.1 Installations:

    In Windows 3.1 and 3.11, the ZIP drive must be loaded by DOS before starting Windows. Iomega provides Tools to make ZIP use easier when you are in Windows 3.x. But these are not necessary to use the drive or disks.


    Windows 95 and up installations:

          You can use DOS mode drivers before starting Windows the same as with Windows 3.x. However, Windows will run with DOS Compatibility Mode, which can slow things down. Also, most of the features available in the Windows 95 ZIP drive programs will not function.

    Assigning a Custom Drive letter:
    To specify a specific Drive Letter for the ZIP drive, click on Start, Settings, Control Panel, System, Device Manager, Disk Drives and find you Zip Drive on the list. Click on Properties, Settings. The bottom box is "Reserved Drive Letters". Since there can be more than one drive, you can reserve a range of letters. If you only have one drive, select the letter you want in both boxes. When you click Ok you will have to restart Windows before the new letter takes effect.


    Loading a ZIP drive with a BOOT DISK

          If you know which files are needed to load your ZIP drive, those are the only ones you will need. By using the techinques in Optimizing Memory usage, you can make an efficient boot disk.

    For the CONFIG.SYS you need:

    device=emm386.exe noems
    devicehigh=aspippm1.sys /info file=nibble.ilm speed= 1 /info
    Use the correct drivers for your drive.

    For the AUTOEXEC.BAT you need:

    lh guest letter=y
    Add whatever other commands you want in the AUTOEXEC.BAT.

    If the above were for your drive, you would need only the following files:

    If you are making a disk for an unknown ZIP drive, you must include the files it MAY need. This can be a problem if disk space is limited. I use both ZIP 100 and ZIP Plus 100 drives. So I include drivers for both. My config.sys includes:
    devicehigh=aspippm1.sys /info file=nibble.ilm speed= 1 /info
    devicehigh=aspippm2.sys /info file=nibble2.ilm speed= 1 /info
    This works for virtually all Parallel Port hookups. It tries each line. Only one of them will load. It reports when it loads.


    If a disk doesn't read, don't assume it is finished.
  • If you are in Windows 9.x, try loading DOS Mode drivers and try to access the disk.
  • In both DOS and Windows modes, if you used the Port Acceleration Program, this sometimes causes a failure.

    If this is DOS Mode, you can find the original settings in OPTIPPM1.OLD in the directory that the GUEST.EXE is run from.

    If this was done in Windows 95, you may be able to recover by copying the SYSTEM.DA0 and USER.DA0 over the SYSTEM.DAT and USER.DAT if Windows has not been restarted after the modification.

    Drive Letter Problems

    If, in Windows 95/98, you have multiple drive letters assigned to the same drive, be sure you are not loading DOS mode drivers. Windows will sometimes load its drivers as well, causing duplication.

    With the ATAPI/IDE drives, the BIOS may assign letter B to the drive. This is done without any driver. If you have a Bootable ZIP disk, the ZIP drive will normally become A drive and the Floppy drive will become B drive. Older BIOS' do not support this. So Software drivers are used like most other type ZIP Drives. However, later BIOS's may support this. But the settings must be correct. You may experience system lockup, multiple drive letter for the drive or inability to access the drive. See My Zip ATAPI drive is assigned drive letter B from IOMEGA's support pages.

    Disk Read Problems

  • If you are at DOS, use the lowest speed setting. NIBBLE.ILM or NIBBLE2.ILM are generally the default file.
  • If you are loading the DOS Mode driver in the CONFIG.SYS, make sure the GUEST.INI is not also operational.
  • Parallel Port Settings: There are several Parallel Port settings on modern computers. Among these are EPP, ECP and EPP/ECP. On some computers the drive may not work in some of these environments. At boot up, enter the BIOS Setup Utility and try different settings for the Parallel port. Keep in mind that other devices such as the Printers and Scanners, may need the settings the way they were. Be sure to test all such devices when you change these settings.
  • Although Iomega disapproves of third-party programs, Steve Gibson's Trouble In Paradise (TIP) tests the disk and Drive for defects. One of my drives failed, and after TIP diagnosed it, Iomega replaced the drive free, even though it was 2.5 years old.

    Iomega's tests consisted of feeding it disk after disk. After they concluded that the drive was defective, they told me never to use those disks again. They did furnish me replacement disks. But fortunately I had no necessary data on those disks. Steve Gibson's test, by contrast, reported the problems on the test screen when the first disk had errors.


    If your drive is experiencing the "Click Of Death" and you can't get warranty replacement or repair, this site might be a last resort:
    Click Of Death Fix. The author shows how to open the case and make some adujustments that might just give an otherwise worthless drive a new chance to be usefull.

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