What would be different about performing a hard-drive-to-tape backup with IDE devices and with SCSI devices? What are the advantages of using SCSI devices over IDE devices for backups?
SCSI transmits the data faster than IDE.
SCSI is also more flexible then IDE: you can only have four IDE drives in a system vs. 15 SCSI drives in a system. One reason why servers use SCSI is that if one of the hard drives goes down, you can keep doing what ever you were doing and replace the drive without turning off the system, and with a good backup program you lose very little ...