IBM TS4500, Introduction And Planning Manual

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A top rack is installed in the field by an IBM service representative on one or more
frames of a TS4500 tape library. The top rack, and any components that are housed
in the rack, are supported and serviced independently of the or TS4500 tape
library.
Feature code 1750, top rack end covers, is required for the left and right ends of
one or more adjacent top racks. This feature is only required for the first top rack
that is ordered when multiple top racks are ordered for adjacent frames.
Feature code 1751, power distribution unit (PDU), can optionally be ordered for
any top rack. Up to two of FC 1751 can be ordered for any top rack. The first PDU
does not use any of the 10U rack space. A second PDU, for redundancy, uses 1U of
rack space. One power cord feature, 9954 through 9959 or 9966, is required for
each PDU that is ordered.
Dual accessors and integrated Service Bays
When an optional second accessor is installed, the TS4500 tape library features
high availability (HA) which enhances the library performance. The extra accessor
enables the library to operate without disruption if any component of one accessor
fails. The integrated Service Bays, reduce unusable service space by 40% compared
Figure 4. TS3500 tape library with top rack installed
Chapter 1. Overview
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