Fixed Blocked Files

CMS filemode 1 files do not have blocked characteristics. When CMS filemode 1 files are used with OS Simulation for blocked record reads and writes, the records are treated as individual units rather than as blocked groups. This causes some problems when OS/MVS block record macro functions, such as READ, WRITE, NOTE, POINT, and BSP (BackSPace), are used on filemode 1 records. Normally these functions return a reference to the block number of a record grouping. However, when CMS filemode 1 files are used with these functions, the records must be logically pseudo-blocked because they exist as individual pieces rather than blocked groups. For Fixed Blocked records, both the size of each record and the size of the block is known, so the OS Simulation code can do a simple calculation to determine the OS/MVS block number reference based on the CMS relative record number, the record length and the block size. Therefore, Fixed Blocked files stored as CMS filemode 1 types will get the same block reference values returned as those stored as filemode 4 types.