Special Notes for OnStream ADR and ADR2 Drives

OnStream currently offers a number of reasonably priced tape drive solutions for Linux users. Capacities on these drives range from 15/30, 30/60, and 60/120GB per tape (initial number is uncompressed capacity).

Supported Drive Models include:

• - These require the DI30 ide-tape patch or osst under IDE-SCSI DI30 - IDE/ATAPI 15/30GB per tape DI30Fast - IDE/ATAPI 15/30GB per tape - supports DMA
• - The SC30 requires the osst driver SC30 - SCSI 15/30GB per tape
• - These drives are either native SCSI or utilize IDE-SCSI emulation. They use the standard st driver and do not require osst. ADR2-60 - IDE/ATAPI 30/60GB per tape ADR2-120 - IDE/ATAPI 60/120GB per tape ADR2-60 - SCSI 30/60GB per tape ADR2-120 - SCSI 60/120GB per tape
• - The USB version use the usbcore, uhci/ohci, usb-storage, and st drivers ADR2-60 - USB 30/60GB per tape

There was also an ADR-50 drive that was a native SCSI drive. It had the same 32K requirement and used the st driver. It is no longer manufactured.

No matter which drive you select, they all use OnStream's ADR formatted tapes. There is only one element that you must be aware of to use these drives successfully under Linux - they require that all data I/O be performed in multiples of 32K chunks.

For most applications, there are arguments that allow you to set the size of the buffer that is used when performing I/O to the ADR tape drives:

tar: use -b 64
tar -cvf /dev/nosst0 -b 64 /home
dd: use bs=32768
dd if=/dev/hda3 of=/dev/nosst0 bs=32768
cpio: use --io-size=32768 and --block-size=64
find . | cpio --create --blocksize=64 --io-size=32768 --file=/dev/nosst0

For other backup utilities, check the avaibility of a setting for bufsize, blocksize, or I/O size and set it to utilize 32K or 32768 bytes.