Ensuring DASD Data Integrity During Media Maintenance
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18
This invention relates to a method for ensuring data integrity during the execution of a media maintenance function by a host CPU upon a DASD (Direct Access Storage Device) storage subsystem. The method comprises the steps of (a) copying data from a selected DASD track to another cylinder on the same volume, the other cylinder not being accessible by way of the host operating system but by way of a host process executing privileged access instructions; (b) performing the media maintenance function; and (c) in the event of a job or system failure, the data is copied from the other cylinder to the selected DASD track. The media maintenance function includes the writing and readback comparison of test patterns to the DASD in order to ascertain surface defects.