TITLE
    Power Macintosh G3: Ultra Wide SCSI Hard Drive Information
Article ID:
Created:
Modified: 		24330
1/23/98
5/12/00
TOPIC

    This article contains important information and specifications for the Ultra Wide SCSI internal hard disk option for Power Macintosh G3 computers.

DISCUSSION

    If your computer came with an Ultra Wide SCSI hard disk drive, the following additional components are installed in your computer:

    • An internal Ultra Wide SCSI hard disk drive (in place of the standard IDE hard disk drive).
    • An Ultra Wide SCSI card in one of your computer's PCI slots.
    • An internal Ultra Wide SCSI-3 chain that supports your internal hard disk and up to two additional internal devices. (The Ultra Wide SCSI-3 chain can transfer data at up to 40 MB per second.)

      Important: Do not connect any SCSI devices to the external 68-pin SCSI-3 connector or the internal 50-pin SCSI-2 connector on the PCI card that supports the internal hard disk. Connecting even one external SCSI device to the external 68-pin connector extends the overall cable length of the SCSI bus beyond the limit for which error-free operation can be guaranteed; the combined length of the internal cable and the external cable reduces the reliability of all the devices connected to the Ultra Wide SCSI-3 bus. Connecting a device to the internal 50-pin SCSI-2 connector on the Ultra Wide SCSI card will cause your Ultra Wide SCSI-3 devices to transfer data at the slower, SCSI-2 rate. However, you can still connect a device to the internal 50-pin SCSI-2 connector on the logic board without affecting the performance of the PCI card.

    About the Ultra Wide SCSI-3 Bus

    You can connect up to three internal devices (including your internal hard disk) to the Ultra Wide SCSI-3 bus on this card. (You can't connect more than three because there isn't enough space in the computer.) All devices on the same SCSI bus must have unique ID numbers, but devices on different SCSI buses may use the same SCSI ID number. (For example, you could have a removable media drive with ID number 3 connected to the Narrow SCSI-1 bus and a hard disk with ID number 3 connected to the Ultra Wide SCSI-3 bus.)

    The hard disk that was installed in your computer at the factory, as well as the SCSI card itself, have already reserved certain SCSI ID numbers on the Ultra Wide SCSI-3 bus. Other ID numbers are available for assignment to SCSI devices that are added later, as described in the following table.
    Ultra Wide SCSI ID number
    Device
    0
    		Factory-installed hard disk drive (terminated)
    1 through 6
    		Available
    7
    		SCSI PCI card (terminated)
    8 through 15
    		Available


    Important : The factory-installed internal hard disk and the SCSI card are both terminated. Other SCSI devices that you install and connect to the Ultra Wide SCSI-3 bus must not be terminated. If you attach a terminated device to the internal SCSI interface, the computer will malfunction. You use the internal ribbon cable with the 68-pin connectors to connect an internal SCSI device to the Ultra Wide SCSI bus.

    U lt ra Wide SCSI Card Specifications
    • Automatic termination
    • Advanced Data Streaming Technology (ADS)
    • RAID ready
    • Embedded RISC I/P processor
    • Ultra SCSI connector: Fine pitch 68-pin "P"
    • Flash ROM BIOS
    • PCI 2.1 compliant
    • Large command FIFO
    • Supports disconnect/reconnect
    • Asynchronous I/O support
    • Multiple initiator support
    • SCSI-3 tagged command queuing
    • SCSI Manager 4.3 compatible


Document Information
Product Area: Computers
Category: Power Macintosh
Sub Category: Power Macintosh G3

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