An open data path (ODP) is the path through which all input/output (I/O) operations for the file are performed. ODPs can be shared by more than one program in the same job but not between jobs.
The object is to be able to share ODPs and still have the applications work as before. Sharing the ODP reduces the amount of main memory the job needs and reduces the amount of time it takes to open and close the file.
The amount of work the operating system does can be reduced by sharing the ODP among all the programs in the jobs that use it. When a file is used more than once in the same job, it can be shared. Sharing an ODP should be done with care. With each access path the position of the current record (the file cursor) is held only once on the ODP. It is possible that one program accessing a file with a shared ODP can change the position in the file inadvertently, causing unpredictable results in other programs in the job.
Sharing an ODP is not defined as a default for access paths. You must specify share ODP on the compiler override for a given access path.
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