ONLINE Command

Displays all volumes online.

]ONLINE

S3,D2 /RAM
S6,D1 ERR=$27
S6,D2 ERR=$27

Accepts slot/drive parameters.

]ONLINE,S3,D2

S3,D2 /RAM

Error code of $57 indicates duplicate volumes are online, and ONLINE reports which disk is a duplicate.

]ONLINE

S6,D1 /MY.DISK
S6,D2 ERR=$57 (S6,D1)