Method and system for synchronization character location and prediction

Abstract

A method and system for locating and predicting synchronization characters within data blocks stored within multiple tracks on a removable data storage medium in a data storage system. The location and identity of each diverse synchronization character within multiple data blocks is predicted in response to an identification of an initial acquisition character and an identification of a particular data storage format. A first synchronization character is predicted and a synchronization counter is then incremented in response to a detection of each subsequent synchronization character, or, in response to the elapse of one of two predetermined delay periods. A system clock delay period is initiated immediately after each synchronization character is detected and the synchronization counter is then incremented at the end of that delay period. A second delay period is initiated thereafter, utilizing a derived track clock signal, which is reasonably insensitive to variations in storage media transport speed. The expiration of this second delay period is then utilized to increment the synchronization counter, if no synchronization character has been detected prior to that occurrence. In this manner, variations in tape speed and an occasional missed synchronization character may be accommodated and the identity and location of predicted synchronization characters may be accurately determined.