Cache control method and apparatus for storing data in a cache memory and for indicating completion of a write request irrespective of whether a record to be accessed exists in an external storage unit

A cache control method executed by a control unit with a cache memory connected with a storage unit for storing records, each record having a respective control field inclusive of a record number and at least another field, and said cache memory storing data of frequently-accessed records of the storage unit, comprising the steps of:

• (a) receiving from a data processing unit a write request including a record number for designating a record to be written, field information for designating a field other than a control field to be written in the designated record, and process mode information for designating a process mode to be executed when said designated record is not being stored in said cache memory;
• (b) receiving, from said data processing unit, data to be written in said designated field in accordance with said process mode information, regardless of whether the designated record is being stored in said cache memory;
• (c) storing said data received in step (b) into said cache memory without accessing said storage unit;
• and
• (d) notifying said data processing unit of a completion of said write request.

A cache control method for a control unit for a cache memory connected with a storage unit having a plurality of physical areas for storing records, each record having a control field inclusive of a record number and at least another field, and said cache memory storing data of frequently-accessed records of the storage unit, wherein said control unit holds, for each physical area, record format condition information representative of whether a condition that there is no duplication in the record numbers of the records in the physical area is satisfied or not, comprising the steps of:

• (a) receiving from a data processing unit a write request including a record number for designating a record to be written, physical area information for designating a physical area to be written, and field information for designating a field other than said control field to be written in the record, and checking whether record format information for said physical area to be written satisfies said condition or not;
• (b) receiving, from said data processing unit, data to be written in said designated field regardless of whether the designated record is being stored in said cache memory;
• (c) storing said data received in step (b) into said cache memory without accessing said storage unit;
• and
• (d) notifying said data processing unit of a completion of said write request.

A cache control method executed by a control unit with a cache memory connected with a storage unit having a plurality of physical areas for storing records, each record having a control field inclusive of a record number and at least another field, and said cache memory storing data of frequently-accessed records of the storage unit, comprising the steps of:

• (a) receiving from a data processing unit a write request including a record number for designating a record to be written, field information for designating a field to be written in the designated record, and record format information representative of whether a physical area which includes the designated record satisfies a predetermined condition that a record number of the record at a start of said physical area is "0" and numbers of following records in said physical area are given in ascending order each incremented by "1", each record in said physical area has one field other than said control field, a length of said one field other than said control field is equal for each record having the record number 1 or larger, and said one field other than said control field of the record having a record number 0 has a predetermined length;
• (b) receiving, from said data processing unit, data to be written in said designated field regardless of whether the designated record is being stored in said cache memory, when the condition of said record format information is satisfied;
• (c) storing said data received in step (b) into said cache memory without accessing said storage unit;
• and
• (d) notifying said data processing unit of a completion of said write request.

A cache control method executed by a control unit with a cache memory connected with a storage unit having a plurality of physical areas for storing records, each record having a control field inclusive of a record number and at least another field, and said cache memory storing data of frequently-accessed records of the storage unit, wherein said control unit holds, for each physical area, record format condition information representative of whether a respective physical area satisfies a predetermined condition that the record number of the record at a start of said physical area is "0" and numbers of following records in said physical area are given in ascending order each incremented by "1", each record in the physical area has one field other than said control field, a length of said one field other than said control field is equal for each record having the record number 1 or larger, and said one field other than said control field of the record having the record number 0 has a predetermined length, comprising the steps of:

• (a) receiving from a data processing unit a write request including a record number for designating a record, and field information for designating a field other than said control field to be written in the designated record;
• (b) receiving, from said data processing unit, data to be written in said designated field regardless of whether the designated record is being stored in said cache memory, in accordance with said record format condition information representing that said predetermined condition is satisfied;
• (c) storing said data received in step (b) into said cache memory without accessing said storage unit;
• and
• (d) notifying said data processing unit of a completion of said write request.

A cache control unit having a cache memory connected with a storage unit for storing records, said cache memory storing data of frequently-accessed records of the storage unit, comprising:

• (a) write request receiving means for receiving from a data processing unit a write request including a record number designating a record to be written;
• (b) data receiving means for receiving, if said designated record is not being stored in said cache memory, data to be written to said designated record from said data processing unit;
• (c) data storing means for storing said received data into said cache memory;
• (d) write request completion notifying means for notifying said data processing unit of a completion of said write request;
• (e) record presence checking means for checking if a record having said record number included in said write request exists in said storage unit;
• (f) data writing means for writing said data stored in said cache memory to said record having said record number included in said write request if said record having said record number included in said write request exists in said storage unit;
• and
• (g) termination notifying means for notifying to said data processing unit if said record having said record number included in said write request does not exist in said storage unit.

A cache control unit having a cache memory connected with a storage unit for storing records, each record having a control field inclusive of a record number and at least another field, and said cache memory storing data of frequently-accessed records of the storage unit, comprising:

• (a) write request receiving means for receiving from a data processing unit a write request including a record number for designating a record to be written, field information for designating a field other than a control field to be written in the designated record, and process mode information for designating a process mode to be executed when said designated record is not being stored in said cache memory;
• (b) data receiving means for receiving, if the designated record is not being stored in said cache memory, data to be written in said designated field from said data processing unit in accordance with said process mode appointed by said process information;
• (c) data storing means for storing said received data into said cache memory;
• and
• (d) write request completion notifying means for notifying said data processing unit of a completion of said write request.

A cache control unit having a cache memory connected between a data processing unit and a storage unit having a plurality of physical areas for storing records, each record having a control field inclusive of a record number and at least another field, and said cache memory storing data of frequently-accessed records of the storage unit, comprising:

• (a) record format information holding means for holding, for each physical area, record format information representative of a condition of whether there is no duplicate record number of the record in the physical area;
• (b) write request receiving means for receiving from a data processing unit a write request including a record number for designating a record, and field information for designating a field other than a control field to be written in the designated record;
• (c) data receiving means for receiving, if the designated record is not being stored in said cache memory, data to be written in said designated field from said data processing unit in accordance with representing that said condition is satisfied or not;
• (d) data storing means for storing said data received by said data receiving means into said cache memory;
• and
• (e) write request completion notifying means for notifying said data processing unit of a completion of said write request.

A cache control unit having a cache memory connected with a storage unit having a plurality of physical areas for storing records, each record having a control field inclusive of a record number and at least another field, and said cache memory storing data of frequently-accessed records of the storage unit, comprising:

• (a) write request receiving means for receiving from a data processing unit a write request including a record number for designating a record to be written, field information for designating a field other than a control field to be written in said record to be written, and information representative of a condition that a record number of a record at a start of the physical area for storing records is "0" and numbers of following records are given in ascending order each incremented by "1", each record has one field other than said control field, a length of said one field other than said control field is equal for each record having the record number 1 or larger, and said one field other than said control field of the record having the record number 0 has a predetermined length;
• (b) data receiving means for receiving, if the designated record is not being stored in said cache memory, data to be written in said field to be written from said data processing unit;
• (c) data storing means for storing said data received by said data receiving means into said cache memory;
• and
• (d) write request completion notifying means for notifying said data processing unit of a completion of said write request.

A cache control unit having a cache memory connected with a storage unit having a plurality of physical areas for storing records, each record having a control field inclusive of a record number, and said cache memory storing data of frequently-accessed records of the storage unit, comprising:

• (a) structural condition information holding means for holding, for each physical area, record format information representative of a condition of whether a record number of the record at a start of the physical area for storing records is "0" and numbers of following records are given in ascending order each incremented by "1" each record has one field other than said control field, a length of said one field other than said control field is equal for each record having the record number 1 or larger, and said one field other than said control field of the record having the record number 0 has a predetermined length;
• (b) write request receiving means for receiving from a data processing unit a write request including a record number for designating a record to be written, and field information for designating a field other than a control field to be written in the designated record;
• (c) data receiving means for receiving, if the designated record is not being stored in said cache memory, said record format information representing whether said condition is satisfied or not, in accordance with data to be written in the appointed field from said data processing unit;
• (d) data storing means for storing said data received by said receiving means into said cache memory;
• and
• (e) write request completion notifying means for notifying said data processing unit of a completion of said write request.