HP 3000 99x Family, Installation Manual

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Chapter 3 3-43
Installation
Installing the System Disk and Tape
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The cable connecting the SCSI system disk to the SCSI card in the internal HP-PB card
cage must be 2.5 meters long. (The base configuration SCSI card is equipped with a
2.5-meter cable.)
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Maximum cable length (including external and internal cables) must not exceed 6
meters.
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If Series 6000 SCSI Mass Storage enclosures are used to house the SCSI disk(s), as is
recommended, no more than two Series 6000 units can be connected in series to the 2.5
meter SCSI interface cable. This is due to the SCSI cable length consumed by the
internal SCSI cable length of 1.4 meter for each Series 6000 unit, and the .5 meter cable
to "daisy chain" from the first Series 600 unit to the second.
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As long as the cabinet containing the SCSI disk drives is immediately next to the SPU,
the disks may be mounted at any position in the rack. It is recommended that SCSI
devices be clustered together to ensure the .5M SCSI cable will accommodate all SCSI
devices.
Fast/Wide SCSI System Disk Guidelines . With HP-UX 9.04 and MPE/iX 5.0, the
Fast/Wide SCSI card (28696A) and Fast/Wide SCSI disks will be supported.
Fast/Wide SCSI has the following configuration guidelines:
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Similar to Single-Ended (S.E.) SCSI, devices on the Fast/Wide SCSI bus are connected
to each other in a "daisy-chain." The first and last devices on the SCSI bus must provide
proper termination on the bus. A terminator, which fits on a SCSI connector, is shipped
with the adapter card and can be used to terminate the last device on the SCSI bus.
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The Fast/Wide SCSI card ships standard with a 2.5 meter 68-in P-connector cable
which supports 16-bit devices.
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The Fast/Wide SCSI card supports up to 15 peripherals. The SCSI address of a device
dictates the device's priority when arbitrating for the SCSI bus. SCSI address "7" is the
address for the highest priority device (and is usually reserved for the host). Address "7"
is followed in priority (from highest to lowest) by the subsequent addresses 6, 5, 4, 3, 2,
1, 0, 15, 14, 13, 12, 11, 10, 9, and 8. Note that for disk arrays only, each F/W SCSI card
supports 7 arrays only, connected to addresses 0 through 7 only. Disk arrays cannot be
connected to addresses 8 through 15. F/W SCSI disk arrays and F/W SCSI disks can be
mixed on the same card.
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Fast/Wide SCSI devices and Single-Ended SCSI devices cannot be mixed on the same
SCSI bus.
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The Fast/Wide SCSI card uses differential transceivers that support distances up to 25
meters. When considering cable distances, however, all cable distances must be added,
including cable from the host to the first storage device, cable consumed within the
storage enclosure, and cable from storage device to storage device.
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There are three types of Fast/Wide SCSI cables:
❏
Standard male-male 68-pin high-density cable which can be used to cable from the
host adapter to the first peripheral, and from peripheral to peripheral. These cables
are available in .9, 2.5, 5, and 10 meter lengths.