TITLE
    PowerBook 5300: Slow SCSI CD-ROM Drives Cause Freezes
Article ID:
Created:
Modified: 		24825
2/25/99
2/25/99
TOPIC

    I have a PowerBook 5300. When I start up from an external CD-ROM drive to try and install Mac OS 8, I continually experience a freeze or crash. Can you help?

DISCUSSION

    Slow SCSI Extension

    Slow SCSI is an extension for PowerBook 5300 series computers that addresses a potential conflict with slow SCSI devices such as 1x CD-ROM drives (for example, the Apple CD150), Zip drives, and PowerBooks in SCSI disk mode. Not all PowerBook computers will experience the conflict, and a PowerBook that does experience the conflict may not experience it all the time (even with different units of the same make and model).

    Important: You should install this extension only if you are experiencing constant freezes or crashes when transferring files with a particular slow SCSI device. Installing this extension will impact performance with all SCSI devices by 10 to 50 percent, so install it only if it is absolutely needed! You can use the Extensions Manager to disable the Slow SCSI extension when it is not needed.

    Installing The Extension

    Option One
    You must start up the PowerBook from a valid System Folder that has the Slow SCSI installed; either from the internal or an external hard drive. Then, when starting from the external CD-ROM, the code from the Slow SCSI extension will have been loaded into the PRAM.

    To install the Slow SCSI Extension, copy it into the Extensions folder and restart.

    Option Two
    If you do not have an external hard drive and the internal hard drive has no valid System Folder, then try the following:

    1. Copy the System Folder from the CD to the internal HD.
    2. Restart.
    3. Then perform the Clean Install.

    OR

    1. Place the Apple CD-ROM extension into the System Folder of the Disk Tools diskette.
    2. Boot from the Disk Tools.
    3. Then perform the Clean Install.

    If you are experiencing difficulty installing from a floppy diskette, do the following:

      1. Start up from the Disk Tools diskette.
      2. Rename System Folder on your hard drive to something such as "old System".
      3. Copy the System Folder from the Disk Tools onto the hard drive.
      4. Copy the Apple CD-ROM extension from the "old System" into the new System Folder just copied onto the hard drive.
      5. Restart from the hard drive.
      6. Perform the Clean Install.

Document Information
Product Area: Computers
Category: PowerBook
Sub Category: PowerBook 5300 Series

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