Cross-System Sharing

With cross-system SHAREOPTIONS 3, you have the added responsibility of passing the VSAM shared information (VSI) and invalidating data and/or index buffers. This can be done by using an informational control record as the low key or first record in the data set. The following information is required to accomplish the necessary index record invalidation:

Number of data control interval splits and index updates for sequence set invalidation
Number of data control area splits for index set invalidation

All data buffers should always be invalidated. See Techniques of Data Sharing for the required procedures for invalidating buffers. To perform selective buffer invalidation, an internal knowledge of the VSAM control blocks is required.

Your program must serialize the following types of requests (precede the request with an ENQ and, when the request completes, issue a DEQ):

All PUT requests.
POINT, GET-direct-NSP, GET-skip, and GET-for-update requests that are followed by a PUT-insert, PUT-update, or ERASE request.
VERIFY requests. When VERIFY is run by VSAM, your program must have exclusive control of the data set.
Sequential GET requests.