公开(公告)号：DE3278888D1

公开(公告)日：1988-09-15

申请号：DE3278888

申请日：1982-01-19

Applicant: IBM

Inventor： HEMPY HARRY O ,  KIRKPATRICK CHARLES RONALD ,  ROBINSON FRANCIS LEROY

IPC: G06F3/06 ,  G06F12/08 ,  G11B20/10

Abstract: In a buffered data recording peripheral system, data is promoted to the buffer (15) in anticipation of a connected host (12) using the promoted data in the near future. In a tape recorder data storage apparatus the actual position of the tape (20) reflects the last promoted data; such actual tape position is "inconsistent" with host operations. If the sequence of host operations continues, such inconsistency actually enhances total operations. When the system detects a change or possible change in future host operations (rewind command, change in tape motion direction, etc.), detect end of file (tape mark) or a change in system operations (load balance affecting drive or deallocation of buffer from drive) the data promoted to the buffer and not read by the host is erased from the buffer. The tape is moved such that upon a forward motion the tape drive would next read data on tape corresponding to the data block erased from the buffer.

公开(公告)号：DE3277991D1

公开(公告)日：1988-02-18

申请号：DE3277991

申请日：1982-02-05

Applicant: IBM

Inventor： BAUER WAYNE JOHN ,  DODT WILLIAM CARL ,  KIRKPATRICK CHARLES RONALD ,  REHAGE TED ANTHONY ,  ROBINSON FRANCIS LEROY ,  TAYLOR WILLIAM KING

IPC: G06F3/06 ,  G06F11/20 ,  G06F13/12 ,  G06F13/38 ,  G06F13/42

公开(公告)号：DE3279629D1

公开(公告)日：1989-05-24

申请号：DE3279629

申请日：1982-01-19

Applicant: IBM

Inventor： FRY SCOTT MILTON ,  HEMPY HARRY O ,  KIRKPATRICK CHARLES RONALD ,  KITTINGER BRUCE EDWARD

IPC: G06F3/06 ,  G06F12/08 ,  G06F12/12 ,  G06F13/12 ,  G06F13/38

Abstract: A data transfer storage system includes host processors (12) which act as utilization devices, a peripheral subsystem (10) having a buffer (15) with buffer segments and devices (13), which act as data source-sinks. … Data transfers between respective buffer segments and data source-sinks, such as peripheral data storage devices are scheduled as a series of transfers based upon most recent, next most recent, etc. usage of the buffer segments by a utilization device. An "MRU-LRU" list of segments ordered by such usage is dynamically maintained. Replacement of segment allocations among devices proceeds from the least recent used, next least recent used, etc. segments. Therefore, the single list controls replacement, read ahead (prefetch) of data from devices to the buffer and transfer of data from the buffer to the devices all based on utilization of the buffer by the utilization device.