IBM 728

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The IBM 728 magnetic tape drive was used on the SAGE AN/FSQ-7 computer. It was physically similar to the IBM 727, but with significantly different specifications.

This is one of several IBM 7 Track tape drives.

tracks	6 Data, 1 synchronization
chars/inch	248 Chars/inch
words	6 chars (32 data bits, 1 odd parity bit, 3 end of file bits)
words/inch	41.33 Words/inch
end of record gap	0.75 Inches - 186 chars - 31 words
Tape speed	75 Inches/sec
Rewind speed	500 Inches/sec (average)
Transfer rate	18,750 Chars/sec - 3,125 Words/sec
Start time	5 Millisec
Stop time	5 Millisec
Width of tape	1/2 Inches
Length of reel	2,400 Feet
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

view • talk • edit	Magnetic tape data storage formats
	Linear	Helical-Scan
Three Quarter Inch (~19 mm)	LINCtape (1962) - DECtape (1963)	Sony DIR (19xx) - Ampex DST (1992)
Half Inch (12.65 mm)	UNISERVO (1951) - IBM 7 Track (1952) - 9 Track (1964) - IBM 3480 (1984) - DLT (1984) - IBM 3590 (1995) - T9840 (1998) - T9940 (2000) - LTO Ultrium (2000) - T10000 (2006)	Redwood SD-3 (1995) - DTF (19xx) - SAIT (2003)
Eight Millimeter (8 mm)	Travan (1995) - IBM 3570 MP (1997)	Data8 (1987) - Mammoth (1994) - AIT (1996) - VXA (1999)
Quarter Inch (6.35 mm)	QIC (1972) - SLR (1986) - Ditto (1992)
Eighth Inch (3.81 mm)	KC Standard, Compact Cassette (1975) - DC100 (1976) - Datassette (1977) - DECtapeII (1979)	DDS/DAT (1989)
Stringy (1.58 - 1.9 mm)	Exatron Stringy Floppy (1979) - ZX Microdrive (1983) - Rotronics Wafadrive (1984)