The PACK command displays the unit numbers, family indexes, and labels of the packs currently on line. On I/O processor (IOP) systems, the channel or base unit identification of the pack string is also displayed. PK and PERPK are synonyms for PACK.

<pack command>

──┬─ PACK ──┬────────────────────────────────────────────────┤
  ├─ PK ────┤
  └─ PERPK ─┘