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For the initial bulk load on a newly installed frame, insert cartridges into the deep slots, but leave the top two rows empty. The slots in the top two rows must be empty for the initial audit of the frame to start, and to enable the initial shuffle operation to proceed. The initial audit fills these slots, and then these slots are used like any other HD slot in subsequent library operations. 

First-generation HD (HD1) frames can be installed to the right side of an Lx5 frame only. 

Second-generation HD (HD2) frames provide the following enhancements: 

GLYPH<SM590000> They can be installed in the leftmost library position (frame position 1). 

GLYPH<SM590000> They offer drive-capable models that support up to 16 HD2-compatible tape drives when in frame position 2 or higher. 

The position and configuration of the frame and the installation of CoD features affect the total available storage capacity of the S25 and S55 frames. Table 1-7 lists the available storage capacity based on possible frame positions and configurations. 

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## 1.2.4 TS4500 High Availability (HA) option 

The TS4500 High Availability (HA) option provides a second accessor for redundancy and performance. This feature allows dual accessors in a dual active mode, and it features an integrated service bay to reduce service space. 

The integrated service bays replace the existing HA frame and Service Bay B frames that are used on the TS3500. The integrated service bays allows a section of a frame to be used for servicing an accessor while the remaining portion of the frame is still available for active storage and drives. Accessor service must be performed through the side, by opening the side doors of integrated service bays. Any HD2 frame can be an integrated service bay. 

