Draft Document for Review February 7, 2020 3:15 pm 8464ch09_Oper.fm Upon selection, a window opens so that a drive can be added to or removed from a library  configuration. Also, you can use this window to share a drive between Logical Libraries and  define a drive as a control path. Figure 9-93 shows the drive assignment window of a logical library that has all drives  assigned. Unassigned drives appear in the Unassigned column with the box selected. To assign them,  select the appropriate drive box under the logical library name and click  Apply . Note:  Do not share drives belonging to a TS7700T. They  must  be exclusive. Click the  Help  link at the upper-right corner of the window that is shown in Figure 9-93 to see  extended help information, such as detailed explanations of all the fields and functions of the  window. The other TS3500 tape library GUI windows provide similar help support. Figure 9-93 Drive Assignment window TS7700T works with the TS1150 tape drives in a homogeneous or heterogeneous  configuration. A heterogeneous configuration of the tape drives means a mix of TS1150  (3592 E08) and one previous generation of the 3592 tape drives to facilitate data migration  from legacy media. Tape drives from previous generation are used only to read legacy media  (JA/JB) while the TS1150 is read/write to the newer media types. Because no writes are  made to the legacy media type, the support for heterogeneous configuration of the tape  drives is deemed limited.  For more information about heterogeneous drive support, see Chapter 2, “Architecture,  components, and functional characteristics” on page 13, and Chapter 8, “Migration” on  page 297. In a multi-platform environment, logical libraries appear as shown in Figure 9-93. Physical  tape drives can be reassigned from one logical library to another. This physical tape drive  reassignment can be easily done for the Open Systems environment, where the tape drives  attach directly to the host systems without a tape controller or VTS/TS7700.  Note:  Work with your IBM SSR when changing the logical library configuration associated  to a TS7700T. The TS7700T needs to be reconfigured to assume the new configuration. Chapter 9. Configuring and operating the IBM TS7700  531