Apparatus and method for detecting and validating formatted blocks on

Abstract

An apparatus and method for detecting and validating formatted blocks during read/write data operations in a magnetic tape data storage system includes component functionality for reading and writing data on a magnetic tape medium in a plurality of modes, including a read-only (R) mode and a read-while-write (RWW) mode, the data being arranged in one or more tracks in a sequence of formatted blocks. In preferred embodiments, formatted block detection and validation is performed by appropriate logic circuitry configured to detect at least one formatting entity representing an inter-block gap, a block acquisition burst, a synchronization character, or any other desired formatting entity, using first and second programmable detection thresholds that are the same or substantially the same in both the R and RWW modes. In addition, a validation determination is made in the RWW mode whether detection of the formatting entity satisfies an RWW error threshold that is greater than either of the first and second programmable detection thresholds. If the RWW error threshold is not satisfied, a message is generated indicating that a write retry may be required. In this way, the detection of various formatting entities is achieved uniformly during the R and RWW modes but provision is also made for applying a more stringent threshold criteria during the RWW mode for write validation.