Device control apparatus and control method
AssigneeFujitsu Limited
InventorNobuyuki Kikuchi
Life of this patent
Estimating the term…
Abstract
A protection data control unit is provided for a cache control unit. In the writing operation to write user data from an upper apparatus into a cache memory, protection data is formed on a data block unit basis of the user data and written into the cache memory. When the interruption of the transfer of the data block is detected during the writing into the cache memory, a forming state of the protection data upon interruption is stored in the cache memory. When the transfer restart of the data block is detected after the interruption, the forming state is returned to the forming state of the protection data upon interruption stored in the cache memory and the formation of the protection data is restarted.
Claims19
A device control apparatus comprising:
- a host interface control unit controlling a communication with an upper apparatus;
- a cache memory in which user data and a management table have been stored;
- a cache control unit controlling said cache memory;
- and
- a main control unit controlling each of said control units by executing a control program stored in a main memory,
- wherein said cache control unit has a protection data control unit controlling such that in a writing operation to write the user data from the upper apparatus into said cache memory, protection data is formed in said user data and written into said cache memory, when an interruption of a transfer of said user data is detected, a forming state of the protection data upon interruption is stored in said cache memory, when a transfer restart of said user data is detected, the forming state is returned to the forming state of the protection data upon interruption stored in said cache memory, and the formation of the protection data is restarted and
- wherein said protection data control unit compares an OP code at the start of transfer which is set by the control program of said main control unit with an OP code during the transfer, detects a transfer interruption when a change in OP code is confirmed, compares an OP code upon interruption with an OP code during the interruption after the transfer interruption, and detects a transfer restart when a change in OP code is confirmed.
A device control method of controlling input/output between an upper apparatus and a device unit through a cache memory, comprising the steps of:
- in a writing operation to write user data from said upper apparatus into said cache memory, forming protection data on a data block unit basis of said user data and writing it into said cache memory;
- when an interruption of a transfer of said data block is detected, storing a forming state of the protection data upon interruption into said cache memory;
- when a transfer restart of said data block is detected, returning a forming state to the forming state of the protection data upon interruption stored in said cache memory and restarting the formation of the protection data;
- and
- wherein an OP code at the start of transfer which is set by a control program is compared with an OP code during the transfer, and when it is confirmed that there is a difference between them, the transfer interruption is detected, and after the transfer interruption, an OP code upon interruption is compared with an OP code during the interruption, and the transfer restart is detected when it is confirmed that there is a difference between them.
Dependencies are inferred from the claim text.