Worm magnetic storage device
AssigneeEMC Corporation
InventorsYuval Ofek, Douglas E. LeCrone
Life of this patent
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Abstract
A method for operating a magnetic disk storage device in read/write and read-only modes. A control program in a system cache memory receives write requests for transferring data to a logical volume. The control program determines whether the write request is directed to a track that is in a read/write or read-only operating mode. Only requests to tracks having a read/write operating mode are enabled to continue. A system administrator or user controls the operating modes for each track in the disk operating system.
Claims18
A method for enabling the selection of at least one group of storage locations in a read/write magnetic disk storage media to operate in a selected one of read-only or read/write operating modes wherein the read/write storage media operates in a system magnetic disk storage system including the storage media and a system cache memory for staging and destaging input-output requests including a writing request for transferring data from a central processor the storage media, said method comprising the steps of:
- A) defining a correspondence in the system cache memory that identifies each storage location group in the magnetic disk storage system having the capability of operating in the two modes,
- B) defining, for each storage location group in the correspondence, one of the read-only and read/write operating modes,
- C) enabling a writing request to alter data in an identified storage location group only when the correspondence in the cache memory specifies that the storage location in the identified group is operating in a read/write mode.
A method for enabling at least one track of storage locations in a magnetic disk storage device to operate in a selected one of read-only or read/write operating modes wherein the magnetic disk storage device operates in a system and includes magnetic disk storage media containing the tracks of storage locations and a device cache memory for receiving writing requests from a central processor and for temporarily storing the writing request and corresponding data and transferring the corresponding data from the device cache memory to at least one track on the magnetic disk storage device, said method comprising the steps of
- A) defining a correspondence in the device cache memory that identifies each track having the capability of operating in the two modes,
- B) defining, for each track identification in the correspondence, one of the read-only and read/write operating modes,
- C) enabling the magnetic disk storage device to transfer data from the device cache memory to a selected track only when the corresponding track identification in the correspondence in the device cache memory specifies that the selected track is operating in a read/write mode.
Dependencies are inferred from the claim text.