IBM R30 Operator's Manual page 44

Tape Cartridge Data Efficiency
Note: For maximum efficiency, operate the 1/4-inch tape drive in the streaming mode
whenever possible.
The 1/4-inch tape cartridge efficiency is defined as the amount of data that can be stored on
the cartridge and the data rate at which the data can be read from the tape cartridge. When
in use, the tape in the cartridge is moved at a constant speed. The speed for the QIC-150 is
72 inches per second. The speed for the QIC-1000 is 80 inches per second. The following
variables affect the amount of data that can be stored on a tape cartridge:
Streaming mode or non-streaming mode
Size of the data file
Number of file marks per file
Tape length
Variable post/preamble
Compatibility mode (QIC-120/QIC-150/QIC-525/QIC-1000)
2-24
Operator Guide