IBM 2401 System/360 tape drives that introduced the 9-track format
10+1/2 in diameter reel of 9-track tape
Full-size reel of 9-track tape
Quarter-inch cartridges
9 Track tape drive used with DEC minicomputers
An IBM 3590 data cartridge can hold up to 10GiB uncompressed.
Inside a 9 Track tape drive. The vacuum columns are the two gray rectangles on the left.
Full size 1/2" tape reel in protective case
Linear serpentine
Two small 1/2" tapes, front and back
Aluminum foil strips mark the start and end of tape
IBM 729V
The write protection ring prevents the tape from being written when removed
A typical library of half-inch magnetic tape
3M 777 High Grade 6250 CPI - Security Computer Tape

The 1⁄2 inch (12.7 mm) wide magnetic tape media and reels have the same size as the earlier IBM 7-track format it replaced, but the new format has eight data tracks and one parity track for a total of nine parallel tracks.

- 9-track tape

Tape was an important medium for primary data storage in early computers, typically using large open reels of 7-track, later 9-track tape.

- Magnetic-tape data storage

The first, used in 6,250 bpi magnetic tape since 1973, is an error-correcting code combined with a run length limited (RLL) encoding scheme, belonging into the group of modulation codes.

- Group coded recording

Various recording methods have been employed during its lifetime as tape speed and data density increased, including PE (phase encoding), GCR (group-coded recording) and NRZI (non-return-to-zero, inverted, sometimes pronounced "nur-zee").

- 9-track tape

Group coded recording was first used for magnetic tape data storage on 9-track reel-to-reel tape.

- Group coded recording

Common 7-track densities started at 200 characters per inch (CPI), then 556, and finally 800; 9-track tapes had densities of 800 (using NRZI), then 1600 (using PE), and finally 6250 (using GCR).

- Magnetic-tape data storage
IBM 2401 System/360 tape drives that introduced the 9-track format

0 related topics with Alpha