MAES Adds Support for VTAM Generic Resources
CleverPath Aion BRE r10 for Mainframe now supports online client access via VTAM Generic Resources to Aion components running in MAES. With Generic Resources, VTAM automatically routes client connection requests to the one member of a "pool" of servers best able to service the client request. Most CICS and IMS client programs require only minor changes to gain the flexibility, reliability and scalability of Generic Resources.
There are many advantages to accessing MAES using Generic Resources. With Generic Resources, each connection request to MAES is routed to the MAES region currently servicing the least workload. If one of the MAES regions in the Generic Resource pool were to unexpectedly terminate, subsequent connection requests would automatically and transparently be routed to other MAES regions. When the terminated region is restarted, it rejoins the pool of available MAES regions and will receive the majority of subsequent connection requests until the workload is equally shared among the MAES regions. The ability to dynamically join the generic resource pool can also be used to add additional capacity. For example, if an unanticipated workload results in unacceptable response times, additional MAES regions can be added to the generic resource pool to service subsequent connection requests.
To access MAES using Generic Resources, MAES's GRNAME value is specified in the MAESNAME field on connection requests for IMS clients or in the NETNAME field in the connection definition for CICS clients. For an explanation of the GRNAME parameter, see the entry for GRNAME in the section titled Specify MAES Run Time Parameters and DD Statements in Chapter 5 of the CleverPath Aion BRE r10 Mainframe User Guide.
In order to access MAES components using generic resources, online client programs must use the ACQUIRE and RELEASE functions. For additional information on using the ACQUIRE and RELEASE functions, see the sections titled Use the XXXX YYYY Component in Chapter 4 of the CleverPath Aion BRE r10 Mainframe User Guide, where XXXX is the execution environment (CICS or IMS) and YYYY is the source language of the online client program (COBOL, PL/I or C).
Sample programs demonstrating use of the ACQUIRE and RELEASE functions are distributed with the CleverPath Aion BRE mainframe product. See the sample client programs ending in '3' in HLQ .SAMPLES.SOURCE for an example in each combination of online execution environment and client source language. The names of the sample programs are coded according to the following legend:
Position Category Codes
1 Program Type CL (Client program)
2 Environment CIC (for CICS) or IMS
3 Language CB (for COBOL), PL (for PL/I) or
4 Functionality 3 - Acquire/Release
For example, the sample client program CLIMSCB3 illustrates the use of ACQUIRE and RELEASE for a COBOL client executing in the IMS environment.