Rack-Mounted Non-SCSI 1/2-Inch Reel Drives

For 1/2-inch rack-mounted tape drives with either a Tapemaster or Xylogics 472 controller, substitute the density from Table 38-4 for the A variable in the device name (/dev/rmt/XA).

Table 38-4 Designating Density for Rack-Mounted 1/2-inch Tape Drives

Character	Density
null	Default "preferred" (highest) density (usually 6250 bpi uncompressed)
l	800 bpi
m	1600 bpi
h	6250 bpi
u	6250 bpi compressed

If you omit the density character, the tape is usually written at its highest density, not compressed.