TITLE
    Macintosh Portable: SCSI Termination Problems (1/95)
Article ID:
Created:
Modified: 		6073
9/30/90
1/19/95
TOPIC



    I have a Macintosh Portable to which I have connected separately either an Apple Tape Backup or external hard drive. In either case, the presence of the SCSI device crashes the SCSI system even though it is terminated correctly.

    Could it be that the Macintosh Portable and other new Apple systems do not generate the initial termination due to a change in the CMOS chip?

DISCUSSION


    There are no known problems using Apple's external SCSI hard drives or the Apple Tape Backup on the Macintosh Portable. However, because the Macintosh Portable doesn't provide termination power (to limit demands on the battery), external SCSI devices connected to the Macintosh Portable must provide that power. That is, they must be powered on and left on while using the Macintosh Portable. Also, the Macintosh Portable should be shut down when connecting or disconnecting peripherals.

    We don't know your Macintosh Portable configuration, the software used, the software versions, the events leading up to the error, or what the error was, but what is described above about termination power is common enough that it bears repeating.

    If by "initial" termination you mean that the Macintosh Portable does not have "built-in" termination, it is just like all other Macintosh systems except for the Macintosh IIfx. They are internally terminated.


    Article Change History:
    09 Jan 1995 - Made article public.
    21 Nov 1994 - Reviewed for technical accuracy.

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