APPL EAS storage estimates

EAS is the estimated number of concurrent sessions this application program will have with other logical units (LU-LU sessions). Accurate coding of the EAS value for your applications can save storage in your system. If your EAS value is specified as lower than the number of sessions that you actually have, sessions would still be established as usual. However, the efficiency of searching for the session representation could be impaired if a smaller table was allocated because of the lower EAS value.

For example, if you estimate that there will be less than 30 sessions with this application, but you let the EAS value default to 509, then an extra 4K table will be allocated from common storage. The size of the table is based on the EAS value that you code and is determined as follows:

Table size	EAS value
4K	30–4000
8K	4001–8000
16K	8001–16000
32K	16001–32000
64K	32001–48000
128K	48001–56000
256K	56001–64000
512K	greater than 64000

Note: For each OPEN ACB with EAS less than 30, one LF buffer will be allocated (for an LUCB) and there will be no additional table storage allocated. If EAS is greater than 30, then one SF buffer will be allocated (for an LUCB) in addition to storage for the table size indicated in the table above.

See z/OS Communications Server: SNA Resource Definition Reference for more information about EAS.