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System Administration Guide

SCSI 1/4-Inch Cartridge and 1/2-Inch Front-Loaded Reel Drives

For SCSI 1/4-inch cartridge and 1/2-inch front-loaded reel drives, substitute the density from Table 38-5for the A variable in the device name (/dev/rmt/XA).

Table 38-5 Designating Format or Density for SCSI Tape Drives

Character 

Density 

1/4-Inch Cartridge 

Density 

1/2-Inch Front-Loaded Reel-to-Reel 

null

Default preferred (highest) density 

Default preferred (highest) density 

l

QIC-11 format 

800 bpi 

m

QIC-24 format 

1600 bpi 

h

QIC-150 

6250 bpi 

u

Reserved 

Reserved 

For 1/4-inch cartridges, density is specified by the format in which the data is written: the QIC format. The QIC-11 and QIC-24 format write approximately 1000 bytes per inch on each track. The density for QIC-150 is somewhat higher. The "preferred" density for a 60-Mbyte 1/4-inch cartridge drive is QIC-24 and for a 150-Mbyte 1/4-inch cartridge drive is QIC-150.

An 18-track drive can write only QIC-150; it cannot be switched to write QIC-24 or QIC-11. Format selection is only useful for drives that can write both QIC-24 and QIC-11.