Most currently-manufactured IDE drives (note that all "IDE" drives are actually "EIDE" now) with a spindle rate of 5400 rpm or higher will work with the ADAT HD24. Higher-speed IDE drives are acceptable as well. The only requirement is that it be ATA-4 compatible. Almost all drives currently sold meet this requirement, and most exceed it by a significant margin. And costs are low: 20 GB drives are available for under $100, which makes them as inexpensive per megabyte as tape. As an aid to our customers, Alesis plans to maintain an approved drive list on the Alesis web site. HD24 does not use SCSI or SCSI-2 drives.