When you open and close data sets, consider the following guidelines:
- Two or more tasks or two or more DCBs can share data sets on DASD.
See Sharing Non-VSAM Data Sets and Sharing PDSEs for more information.
- The system can override volume disposition specified in the OPEN
or CLOSE macro if necessary. However, you need not be concerned; the
system automatically requests the mounting and demounting of volumes,
depending on the availability of devices at a particular time. For
more information about volume disposition see z/OS MVS JCL User's Guide.