Silicon Graphics International Corporation

John Michael Sygulla

Kevan Flint Rehm

Joseph Carl Nemeth

Judith Ann Schmitz

Arun Ramakrishnan

Greg Slowiak

Data state rollover is performed based on data state snapshots and deltas. A series of snapshots is taken of the current data state, an original data state, and data states in between. Deltas are then generated between two sequential snapshots. This results in numerous deltas which represent the difference between consecutive snapshots. Once the deltas are acquired, the deltas may be stored along with the snapshot of the present data state. As such, previous data states may be rolled back to by determining the number of deltas to apply to the current data state to achieve the desired previous data state. In cases where the rollback or rollover fails, deltas may be played against the current data state to a point where the last known trusted and working data point existed.

Hierarchical system manager rollback

A two part process is used for modifying records to be written and retrieved from tape devices. A record is appended with a cyclic redundancy check and a string of zeros. Submitting the entire record to tape drives which are logical block protection enabled will result in no change. For drives that are not LBP enabled, the string of zeros at the end of the record is removed. In addition to determining whether a drive is LBP compliant, a determination may be made as to whether a drive is a linear tape open drive from a particular manufacturer. Linear tape open drives may behave similarly as drives which may not be enabled with logical block protection.

Growing community of inventors

Chippewa Falls, WI, United States of America

John Michael Sygulla