公开(公告)号：WO1988002539A1

公开(公告)日：1988-04-07

申请号：PCT/US1987002469

申请日：1987-09-25

Applicant: STORAGE TECHNOLOGY CORPORATION

Inventor： STORAGE TECHNOLOGY CORPORATION ,  HUNTER, Dan, A. ,  OPPERMAN, Lawrence, F. ,  GOORAS, George

IPC: G11B15/18

CPC classification number: G11B27/17 ,  G11B15/093 ,  G11B2220/90

Abstract: An early end of tape sensing subsystem for a data processing system, including a host computer, a cache buffer (35), and a magnetic tape drive subsystem utilizes outputs dependent upon the movement of a capstan wheel (11), swing arm (13), and file reel (15) of the magnetic tape drive subsystem, determining the net movement therein in order to mesure the circumference of the file reel (15) plus tape thereon. Whenever a series of valid readings from a conventional sensor (41) are obtained indicating that the circumference of the file reel (15) plus tape is approaching that of the circumference of the file reel (15) itself (i.e., no tape on the file reel (15)), a signal is sent to a microprocessor (33) controlling the cache buffer (35), said signal indicating that the end of the tape is approaching.