Silicon Graphics CHALLENGE L, User Manual, Page: 58 / 164

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Chapter 4: Installing Optional Peripherals
It is important to know the exact type of drive and the protocols it uses
before you configure and connect it to your system. If you are unsure,
contact your sales representative or service provider before the installation;
otherwise, you may degrade SCSI performance or crash your system.
Note: This product requires the use of external shielded cables in order to
maintain compliance with Part 15 of the FCC rules.
If you are going to have an authorized service provider install peripherals,
add external SCSI devices, or reconfigure SCSI bus channels, be sure they
understand the rules in the following list.
Caution: Improper SCSI implementation will cause degraded system
performance, a system crash, and/or possible damage to the hardware.
• If you plug a single-ended drive into a bus configured for differential
operation, nothing on the bus will work.
• If you plug a differential drive into a bus configured as single-ended,
the differential drive will not work. Single-ended drives on the bus may
continue to work.
• Configuration jumpers at the IO4, drive rack backplane, and the sled
board must all be set for the same mode or the bus will not work.
• Front-loading SCSI devices, both half-height and full-height, that are
installed in front-loading bays do not require terminators. Any
terminators mounted on a drive should be pulled out before installing a
device in a Challenge system.
Caution: Never use a single-ended SCSI terminator on a differential
channel. Connecting a single-ended terminator to a differential channel
will short +5V directly to ground, resulting in blown fuses and possible
equipment damage.
• Using a differential terminator on a single-ended bus will cause SCSI
bus malfunction.