There are various Components in a EMC Symmetrix series of machines.

To name a few

Disk Directors
Channel Directors (CA, FA, EA, FI, GI, FA2)
Memory Cards
Disk Drives
Power Supply
For 3 Bay cabinets (AC-DC PS and DC-DC PS)
Fan
Back End Disk Adapters
Back End Channel Adapters (CA, FA, EA, FI, GI, FA2)
Communication Card
EPO Module
Battery
Service Processor

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