Product data

SCSI Interface Cards
The SCSI interface card of the 2104:
v Provides SCSI Enclosure Services (SES).
v Reads the VPD from the backplanes and the fan-and-power-supply assemblies.
v Controls the Subsystem Check light and the disk drive module Check lights.
v Controls the speed of the fan of the fan-and-power-supply assemblies or
fan-and-power-supply assembly and fan assembly.
v Monitors the Emergency Power Off Warning (EPOW) signal from the power-supply
assembly or assemblies. If an EPOWsignal occurs, the SCSI interface card sends
a SCSI Resetsignal to all the disk drive modules.
v Provides support for the hot plugging of the disk drive modules.
v Monitors itself. The SCSI interface card detects a self-failure if:
The microprocessor fails.
An SES function fails.
The enclosure temperature is outside the specified limits.
v Provides support for SCSI Ultra 160 MB per second operation, LVD (Low Voltage
Differential) mode.
Note: It does not provide support for SE (Single Ended) mode.
If the 2104 has two SCSI interface cards, each SCSI interface card can be accessed to
collect enclosure information only if it is connected to a SCSI attachment. If both cards
are operational, the SES-active card provides all the functions described here. The
other card only detects self-failure and drives the internal SCSI bus.
Error Logging
Errors that the 2104 detects are not automatically logged to the system error log.
To collect error data, run diagnostics. For more details, see Collecting Errors in
Appendix A. Additional Information for RISC Systems.
Configurations
Each SCSI interface card can be attached to only one using system. A 2104 that has
one SCSI interface card can, therefore, be attached to only one using system. A 2104
that has two SCSI interface cards can be attached to two using systems. No SCSI
terminators are needed.
Chapter 1. Reference Information 3