| 摘要 |
The invention enables reduction of latency time for receipt of data which has been requested from a disk system. The method enables use of a read command which enables a cache memory output to occur only when the read command has been completed. The method of the invention initially receives a read request from a host processor for a number of data blocks on a disk track (referred to as requested blocks), the requested blocks being a subset of blocks stored in the disk track. If the requested blocks are not already stored in a cache memory, the method constructs at least a first command to transfer the track to cache memory, the first command enabling identification of a last data block of the requested blocks. A second command is also prepared to transfer the track to cache memory, the second command enabling identification of the last block of the remaining set of blocks in the track. Thereafter, the first command is executed and when the last block of the requested blocks has been transferred to cache memory, indicating completion of the first command, transfer of the requested blocks from cache memory to the host processor is commenced. The second command is also executed and enables a staging of the remaining blocks of the disk track to cache memory, thereby assuring that the entire track resides in cache memory.
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