Editing IBM 729 (section)

[[Image:IBM 729 Tape Drives.nasa.jpg|thumb|280px|A bank of IBM 729 tape drives]]
[[Image:Tapesticker.jpg|thumb|Reel of tape showing beginning-of-tape reflective marker]]
[[File:IBM 729 restored.jpg|thumb|An IBM 729 tape drive being debugged as part of the [[Computer History Museum]]'s [[IBM 1401]] restoration project. A reel of magnetic tape is being loaded onto the drive. The operator's finger is holding the tape in place on the take-up reel as he takes a few turns to secure the tape leader. An [[IBM 1403]] line printer is in the foreground.]]

The '''IBM 729 Magnetic Tape Unit''' was IBM's [[magnetic tape|tape]] mass storage system from the late 1950s through the mid-1960s. Part of the [[IBM 7-track]] family of tape units, it was used on [[IBM 700/7000 series|late 700, most 7000]] and many [[IBM 1400 series|1400]] series computers. Like its predecessor, the [[IBM 727]] and many successors, the 729 used {{convert|1/2|in|mm}} [[magnetic tape]] up to {{convert|2400|ft|m}} long wound on reels up to {{convert|10+1/2|in|mm}} diameter. To allow rapid tape acceleration (and thus reduced seek/access times), long [[Vacuum column (tape drive)|vacuum columns]] were placed between the tape reels and the [[tape head|read/write heads]] to absorb sudden increases in tape tension which would otherwise break the tape. [[Write protection]] was provided by a removable plastic ring in the back of the tape reel.