IBM 727
From Wikipedia, the free encyclopedia
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 vacuum tube era computer systems. It was withdrawn on May 12, 1971.
The tape had seven parallel tracks, six for data and one to maintain parity. Tapes with character data (BCD) were recorded in even parity. Binary tapes used odd parity. Aluminum strips were glued several feet from the ends of the tape to serve as logical beginning and end of tape markers. Write protection was provided by a removable plastic ring in the back of the tape reel.
| tracks | 6 Data, 1 parity |
| chars/inch | 200 Chars/inch |
| Tape speed | 75 Inches/sec |
| Rewind speed | 500 Inches/sec (average) |
| Transfer rate | 15,000 Chars/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 |
[edit] External link
| Magnetic tape data storage formats | ||
|---|---|---|
| Linear | Helical-Scan | |
| Three Quarter Inch (~19 mm) |
||
| Half Inch (12.65 mm) |
UNISERVO (1951) - IBM 7 Track (1952) - IBM 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) |
|
| Quarter Inch (6.35 mm) |
||
| Four Millimeter (3.8 mm) |
DDS/DAT (1989) |
|
| One Eighth Inch (3.18 mm) |
KC Standard, Compact Cassette (1975) - Datassette (1977) |
|
| Stringy (1.58 - 1.9 mm) |
Exatron Stringy Floppy (1979) - ZX Microdrive (1983) - Rotronics Wafadrive (1984) |
|
 |
This computer hardware-related article is a stub. You can help Wikipedia by expanding it. |
 |
This computer storage-related article is a stub. You can help Wikipedia by expanding it. |
