Benefits of OPENAPI Support

The main reason for providing support for OPENAPI programs is to allow you to move application workloads off the QR TCB onto multiple open TCBs. This allows the possibility of better utilization of machine resources to achieve better throughput.

Another reason that you might want to use OPENAPI programs could be to allow the use of other (non CICS®) APIs.

Use of other APIs is possible because, if an open TCB is blocked by an operating system wait, then only the single application is affected not the whole of CICS, which would be the case if they executed under the QR TCB. Such OPENAPI programs are not permitted to execute on the QR TCB precisely because of this risk of blocking the TCB by an operating system wait and thus affecting the whole of CICS.
  • Use of other (non CICS) APIs within CICS is entirely at the discretion and risk of the user. No testing of other (non CICS) APIs within CICS has been undertaken and use of such APIs is not supported by IBM® Service.