VM/SP Checkpoint Initialization Performance Improvement
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
The Multi-Server technique described herein significantly reduces the time needed to initialize the Virtual Machine/System Product (VM/SP) when a checkpoint start is required. Shortening of checkpoint initialization time is accomplished by systematically arranging all of the SPOOL file blocks (SFBs) in main storage queues and starting a large number of tasks or servers concurrently, thereby greatly reducing the time required to reconstruct the SPOOL space. VM/SP initialization involves determining the extent and status of all the system resources. The single most time-consuming process can be the reconstruction of SPOOL space status, that is, identifying those cylinders and pages allocated to existing SPOOL files and those available for allocation. The SPOOL space status is kept in both cylinder and page allocation maps.