| 摘要 |
An early end of tape sensing subsystem for a data processing system, including a host computer, a cache buffer, and a magnetic tape drive subsystem utilizes outputs dependent upon the movement of a capstan wheel, swing arm, and file reel of the magnetic tape drive subsystem, determining the net movement of tape therein in order to measure the circumference of the file reel plus tape thereon. Whenever a series of valid readings from a conventional sensor are obtained indicating that the circumference of the file reel plus tape is approaching that of the circumference of the file reel itself (i.e., no tape on the file reel), a signal is sent to the microprocessor controlling the cache buffer, said signal indicating that the end of the tape is approaching. |
