In previous versions of this software, an empty VSAM data set, for example a data set that had just been defined, did not show as being empty. As a result, some of the IDCAMS commands that MFJAMS emulates, for example REPRO and PRINT, processed zero records and generated a condition code of 0.
This behavior differs from the corresponding mainframe IDCAMS utility for newly-defined VSAM data sets which generates I/O errors with a condition code of 12.
The behavior of MFJAMS is now consistent with that of IDCAMS.
When a new VSAM file is defined, its virgin file state is recorded in the catalog. Each request to the catalog for information about the file includes a check for the virgin status until the status is changed to non-virgin.
After that, no further checks are performed unless the user defined the file location using the ;MFE:%PCDSN extension to IDCAMS.
If you want to overlay a non-virgin file with a virgin one and have the catalog detect the virgin state, the original file definition using IDCAMS DEFINE must include the file location using the ;MFE:%PCDSN extension to IDCAMS.