| 摘要 |
A buffer stores a plurality of records read from a mass storage device. The buffer includes a record information field and an error flag field for each stored record. The record information field includes count, key and data fields, together with an optional error data field for storing error data indicating a characteristic of an error which occurred when the record was read from the mass storage device. The error data field is typically located adjacent to the field which caused the error. The error flag field stores information indicating whether an error occurred when the record was read from the mass storage device. The error flag field also indicates whether the error was a permanent error. When the host processor requests from the buffer a record which has an error associated with it, the host is informed that the error occurred and is provided with the error data and the record data. If the error was a permanent error, then a unit check is provided to the host for indicating that the record data is not valid. The invention allows the host processor to be aware that the data in the cache buffer contains corrected errors, and also means that host processor need not waste time trying to retrieve data that the cache has already failed to retrieve. <IMAGE> |
