Scsi Drive Rack; Cooling System - Silicon Graphics POWER CHALLENGE User Manual

Chapter 2: Touring the Chassis

SCSI Drive Rack

Cooling System

24
The SCSI drive rack (shown in Figure 2-5) is a vertically oriented enclosure,
with seven half-height drive bays. Each bay is defined by a sheet-metal drive
tray. The SCSI drive sled slides into the tray and locks in place with its
connectors pushed into the SCSI backplane. The sheet-metal drive trays can
be removed to allow the installation of full-height devices.
The internal SCSI backplane provides a maximum of two SCSI channels. The
channels are terminated on the backplane and are not used to control
externally mounted SCSI devices. The channels are compatible with either
8-bit or 16-bit SCSI buses, and they are configured at the factory to support
single-ended and differential SCSI devices in the drive rack. Channel A is set
to single-ended and channel B to differential operation.
It is important that the operational setting on the drive sled printed
Note:
circuit board agree with the setting of the IO4 SCSI channel. If you are
installing a single-ended device in the internal rack, the drive should be
plugged into channel A on the sled board. If you are installing a differential
device, it should plug into channel B on the sled board. Chapter 4 provides
details of what happens if you violate these guidelines.
Caution: Never plug a front-loading or external SCSI device into your
Challenge while the system is powered on.
The Challenge deskside chassis is cooled by a combination of one rotary
"blower box" and two conventional 5-inch (12.7 cm) fans that draw in
ambient air. The 9.7-inch (24.6 cm) vaned rotor provides the main chassis
cooling by drawing air in through openings near the top and exhausting it
out the lower side and rear. See Figure 2-7.
One 5-inch fan cools the system power supply, while the other draws air
from front to back, helping to cool the drive tray assembly.
Caution: Never operate your Challenge system with any of its sheet-metal
panels open or removed. The system will overheat, and damage to internal
components may result.