8464ch07_Upgrade.fm Draft Document for Review February 7, 2020 3:15 pm A frame that contains the back-end switches can still house up to 12 or 16 drives (based on  TS3500 or TS4500). FC 4879 supplies the mounting hardware for the back-end switches and  a pair of dressed eight fiber cable trunks to connect the back-end switches to the associated  back-end drives in the frame.  Only eight pairs are supplied in the trunks because the preferred practice for  TS7770T/TS7760T drive placement states that the drives should be split evenly between two  frames. Drives that do not attach to the back-end switches must be cabled directly to the  drives because the patch panel was removed. Note:  The TS7770T/TS7760T does not support 4 Gbps and 8 Gbps fiber switches for  connection to the back-end drives. Currently, a TS7770T/TS7760T must use the 16 Gbps  fiber switch to connect to the back-end drives. The feasible combination of TS7700, TSx500, and the necessary switches are listed in  Table 7-1. a. TS3500 top rack required due to size of switches Machine with code  R5.0 TS3500 with 4 or 8 Gb drive switch TS3500 with 16 Gb  drive switch a TS4500 with 16 Gb  drive switch TS7770T/TS7760T N/A Homogeneous with  all generation drives Heterogeneous with  TS1150 and TS1140 Table 7-1 Combination of TS7700, TSx500, and the necessary switches Chapter 7. Hardware configurations and upgrade considerations  251