The IBM 728 magnetic tape drive was used on the SAGE AN/FSQ-7

AN/FSQ-7

The AN/FSQ-7 was a computer model developed and built in the 1950s by IBM in partnership with the US Air Force. Fifty-two were built and used for command and control functions for the Semi Automatic Ground Environment air-defense system...

 computer. It was physically similar to the IBM 727

IBM 727

The IBM 727 Magnetic Tape Unit was announced for the IBM 701 and IBM 702 on September 25, 1953. It became IBM's standard tape drive for their early vacuum tube era computer systems. Later vacuum tube machines and first-generation transistor computers used the IBM 729-series tape drive...

, but with significantly different specifications.

This is one of several IBM 7 track

IBM 7 Track

IBM's first magnetic tape data storage devices, introduced in 1952, use what is now generally known as 7 track tape. The magnetic tape is 1/2" wide and there are 6 data tracks plus 1 parity track for a total of 7 parallel tracks that span the length of the tape...

tape drives.

tracks	6 Data, 1 synchronization
char/inch	248 char/inch
words	6 chars (32 data bits, 1 odd parity bit, 3 end of file bits)
word/inch	41.33 word/inch
end of record gap	0.75 inch - 186 chars - 31 words
Tape speed	75 inch/s
Rewind speed	500 inch/s (average)
Transfer rate	18,750 char/s - 3,125 word/s
Start time	5 ms
Stop time	5 ms
Width of tape	1/2 inch
Length of reel	2400 ft (731.5 m)
Composition	Mylar or cellulose acetate base

Tape Word Bit Positions

-----------------------------> Tape travel
LS L6 L12 R2 R8 R14
L1 L7 L13 R3 R9 R15
L2 L8 L14 R4 R10 P
SYN SYN SYN SYN SYN SYN
L3 L9 L15 R5 R11 EOF
L4 L10 RS R6 R12 EOF
L5 L11 R1 R7 R13 EOF
-----------------------------> Tape travel