A technical question (SCSI)

Hello everyone,
This is the (stupid?) question. I have an external SCSI HD, can I shutdown this while the mpc is in function and then turn on?
It's true that i can't disconnect the hd while the mpc is in function?
(i feel like a stupid!)
Thank you very much

do not connect and disconnect scsi devices while the mpc or the scsi device is powered on because it can cause you to burn the scsi fuse out.... or who knows what else. Just dont do it to be safe.