Method and apparatus for managing data on rewritable media to define read/write operational status

DETAILED DESCRIPTION The method and apparatus for managing data on rewritable media are used to define the read/write operational status required for a drive element to read/write data on a rewritable media by making the media self-defining.
The preferred embodiment disclosed herein is a tape drive that reads/writes data records in helical scan format on a magnetic tape that is housed in a single reel magnetic tape cartridge.
This magnetic tape cartridge can be mounted on tape drives connected to different host computers and therefore host computer management of the file safe status and data format of the magnetic tape is not effective.
The phrase "file safe" is used herein to identify media that contains data that must not be modified.
Additional data can be written to file safe media in locations thereon that do not presently contain data.
Tape Drive System Architecture The apparatus illustrated in FIG.
3 represents the tape transport elements found in a helical scan tape drive 300 that are used to read and write data on magnetic tape 100.
The magnetic tape 100 is wound on a single reel 110 which rotates around spindle 111 within magnetic tape cartridge 301.
In helical scan tape drive 300, magnetic tape 100 from magnetic tape cartridge 301 is threaded in direction A past a fixed full width erase head 310, scanner 320 (which contains two pairs of helical read heads 322 and two pairs of helical write heads 321 and one pair of erase heads 323), a fixed longitudinal erase head 331 and a fixed longitudinal read/write head 332.
The magnetic tape 100 then passes around guide 340, over capstan 341 to be wound on machine reel 360 (takeup reel), which rotates around spindle 361.
The full width erase head 310 erases the entire width of magnetic tape 100 and is used when data is recorded on virgin tape.
It is also used when data is recorded on a previously used magnetic tape, if none of the data previously recorded on magnetic tape 100 is to be preserved and the entire magnetic tape 100 is overwritten with new data