The EAS operand on the APPL definition statement indicates the amount of storage to allocate for a table that contains information about any sessions with the application program. The EAS value that you choose can affect performance in your system.

Specifying an EAS value that is too small can cause an increase in path length for VTAM® processing of inbound data flows. The increase is because of VTAM scanning control blocks for some of the sessions. As more sessions become active, the directory entries are used more frequently, and the chains become longer. Longer chains require more scan time. If you specify a larger EAS value, the chains for particular directory entries may be smaller and may use less CPU time for scanning the chains.

For a non-TSO application program, you should specify an EAS value that equals the average number of sessions, but does not exceed 32 767. If you have virtual storage constraints, you can specify a smaller EAS value.

For a TSO application program, you should specify EAS=1.