I have an old 2600 rx HP server and an external tape DAT drive which ised wide SCSI (68 pins). Do I have to power on the tape before the server, or is it the same if I power on the tape after turning on the server?

I read somewhere that turning on the power of SCSI tape after the boot up of server can damage the SCSI bus. It this true?


The SCSI bus can handle powering on of devices while the host is up, effectively all SCSI devices are equal so order of powering on can't matter electrically.

What can matter is whether the operating system is smart enough to detect devices that are powered on after booting, i.e. whether the SCSI bus is scanned again or only once during booting. If it doesn't scan again, then you need to boot with the SCSI peripherals powered up; after booting you should be able to power down those devices until such time you need to use them.

I remember that on SCO Unix you needed to recompile / relink the kernel to hardcode the SCSI ID of a tape streamer or disks, as SCO Unix did no scanning whatsoever. There you didn't need to have the devices switched on during boot...

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