Reading OS/MVS Data Sets
CMS users can read OS/MVS sequential and partitioned data sets that reside on OS/MVS disks. The CMS MOVEFILE command can be used to manipulate those data sets, and the OS/MVS QSAM, BPAM, and BSAM macros can be executed under CMS to read them.
The following OS/MVS BSAM, BPAM, and QSAM macros can be used with CMS to read OS/MVS data sets and DOS files:
BLDL | ENQ | RDJFCB |
BSP | FIND | READ |
CHECK | GET | SYNADAF |
CLOSE | NOTE | SYNADRLS |
DEQ | POINT | WAIT |
DEVTYPE | POST |
- Split cylinders
- User labels
- Track overflow
- Alternate tracks.
As in OS, the CMS support of the BSP macro produces a return code of 4 when trying to backspace over a tape mark or when a beginning of an extent is found on an OS/MVS data set. If the data set contains split cylinders, an attempt to backspace within an extent resulting in a cylinder switch also produces a return code of 4. When a data set has been allocated or updated by OS/MVS on an OS/MVS disk, an OS/MVS CLOSE must be issued before CMS can read or move it. Attempting to read an empty data set on an OS disk is not supported and the results will be unpredictable.