System for monitoring a library unit shared as input/output with higher level unit wherein abnormal occupation of library by a higher level unit is reset

Patent 5594922 Issued on January 14, 1997. Estimated Expiration Date:

September 6, 2014. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

Transfer system for multi-variable control units
Patent #: 4276593
Issued on: 06/30/1981
Inventor: Hansen

SCSI device having transfer parameter storage memory blocks which correspond to each apparatus
Patent #: 5283872
Issued on: 02/01/1994
Inventor: Ohnishi

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Patent #: 5386545
Issued on: 01/31/1995
Inventor: Gombos, Jr., et al.

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Issued on: 09/26/1995
Inventor: Choi

Inventors

Assignee

Fujitsu Limited

Application

No. 301128 filed on 09/06/1994

US Classes:

710/17, Availability monitoring710/107Bus access regulation

Examiners

Primary: Lee, Thomas C.
Assistant: Chen, Anderson I.

Attorney, Agent or Firm

Greer, Burns & Crain, Ltd.

Foreign Patent References

04359353 JP. 12/12/1992

International Classes

G06F 013/10
837

Foreign Application Priority Data

1993-12-13 JP

Abstract

A plurality of higher-level units are connected to a library unit, for example, as a lower-level unit through an SCSI. Furthermore, the plurality of higher-level units are connected by means of a communication path to mutually exchange information regarding the status of use of SCSI for the access to the lower-level library unit. A monitoring control section is provided in each of the plurality of higher-level units to instruct necessary processing in response to the status of use of SCSI. Particularly, when an abnormal occupation of SCSI caused by hang-up of any other higher-level unit is detected by the monitoring control section of a higher-level unit, the higher-level unit instructs its own SCSI controller to reset the bus to achieve bus reset of the other SCSI controller, thus releasing the occupation.