Product data

The 2104 Models DU3 and TU3 can contain up to 14 SCSI disk drive modules. These
modules can be a mixture of various types, which vary in size (see “Chapter 4. Parts
Catalog” on page 123).
The 2104 can be disconnected from its related SCSI attachments (for example, SCSI
adapters) while the using system is running. Also, most of the field-replaceable units
(FRUs) of the 2104 can be removed and replaced while the 2104 and the using system
are running. For a list of those FRUs, see “Concurrent Maintenance” on page 67.
The 2104 has two fan-and-power-supply assemblies, or one fan-and-power-supply
assembly and one fan assembly, to provide all the necessary power and cooling. It also
has up to two SCSI interface cards, which monitor and control the various functions of
the 2104 (see also “SCSI Interface Cards” on page 3). Each SCSI interface card can be
accessed to collect enclosure information only if it is connected to a SCSI attachment. A
switch card assembly provides option selection switches (see also “Switch Card
Assembly Switches” on page 9).
The 2104 can be configured to the using system as a device if applicable. See
“Configuring a 2104 to the Using System” in “Appendix A. Additional Information for
RISC Systems”. When a 2104 is configured as a device:
v Errors that are detected in the 2104 can be collected by the diagnostics.
v Vital product data (VPD) for the 2104 can be accessed.
Most FRUs contain their own vital product data (VPD). A using system can access this
VPD while the 2104 is being configured.
Enclosure configuration information is stored in several locations in the 2104 to allow
concurrent replacement of FRUs. When a new FRU is installed, any special
configuration information that is required by that FRU is read from other locations in the
2104. That information is then used to update the new FRU. To ensure that the
configuration is not corrupted or changed, always exchange FRUs one at a time.
2 2104 Service Guide