ULTRA2 LVD SCSI HOST ADAPTER
4.2 Attaching Other SCSI Devices to the Adapter’s Bus
You can connect as many as fifteen internal and external SCSI devices to your Ultra2 LVD SCSI Host Adapter. Follow the directions listed in this section. (If you are connecting SCSI devices to multiple Adapters to form a clustered system, refer to Section 4.5.)
4.2.1CONNECTING INTERNAL SCSI DEVICES
If you are connecting internal SCSI devices, make sure to use a SCSI ribbon cable that (a) is not too long (see Section 3.3), (b) has the appropriate characteristics (see Section 3.3), and (c) has enough connectors to accommodate the Adapter and all of your internal peripherals. Figure
Terminator
Connect | (Connect remaining | Connect 2nd | Connect 1st |
to the | SCSI devices to other | SCSI device | SCSI device |
Adapter | intermediate connectors) | here | here |
Figure 4-3. The Adapter’s included internal ribbon cable.
This cable is 125 cm (4.1 ft.) long; whether you use it or some other cable, keep in mind that the total length of cable on the Adapter’s SCSI bus, including both internal and external cables, mustn’t exceed 12 m (39.4 ft.) unless you’re attaching one and only one peripheral, in which case you can run as far as 25 m (82 ft.). And this assumes that all of your devices are Ultra2 SCSI LVD compliant; if you are attaching any legacy devices, the maximum total bus length will be much less:
•6 m (19.7 ft.) if the only legacy devices attached to the bus are
•3 m (9.8 ft.) if you have four or fewer devices attached to the bus and any of them are Ultra SCSI
•1.5 m (4.9 ft.) if you have five or more devices attached to the bus and any of them are Ultra SCSI
The cable should have an impedance of at least 120±8 ohms if any Ultra2 SCSI LVD devices are attached; the impedance can be as low as 90±8 ohms only if all attached devices are
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