Shared Spool Configuration – Without an ENQ-Handling Product

This environment is identical to the previous environment except that no ENQ handling product is employed. Another difference is that the shared Spool might or might not be connected to CPU B.

You should not use this configuration.

Only one Control‑M monitor is required for handling the entire shared SPOOL complex. Aside from the following restrictions, all the capabilities also apply to this configuration:

• To avoid jeopardizing data integrity, the Control‑M Repository must not be updated from CPU B. Therefore, all Control‑M components (Monitor, Newday procedure, utilities, KSLs that update IOA and Control‑M files, and so on) must run exclusively on CPU A.
• If the optional CMEM facility is operated on both CPU A and CPU B CMEM must be given read access to the IOA LOAD library and Control‑M monitor to-subsystem Communication file plus write access to the subsystem-to-Control‑M monitor Communication file. All files that are required by CMEM must reside on a shared disk. This shared disk does not need to contain general IOA and Control‑M files. (CMEM can operate in a multi-CPU environment without an ENQ handling product.)
• To make sure that Control‑M files are not updated from CPU B, one or both of the following options must be implemented:
  • Option 1: Use your site’s security product (RACF, ACF2 or Top Secret) to deny write or update access to the IOA and Control‑M files from CPU B.
  • Option 2: Vary off-line (under CPU B) the disks on which IOA and Control‑M files reside. This method is applicable only if the disks do not contain other files. There may also be a problem if CMEM is operated.

  Option 2 is the most effective method, but may be difficult to implement at most sites, because Control‑M uses only a portion of a disk and does not require a dedicated disk. Option 1 is the easiest to implement at most sites.

  As illustrated in the diagram above, terminal TERM 2 is physically connected to CPU B. However, this terminal can be used to operate the IOA Online Facility.

If CPU A and CPU B maintain an appropriate cross-domain SNA connection through a CTC, 37xx communication controller (or equivalent) or Token Ring connection, then the terminal user can log on to VTAM application running in CPU A and invoke the IOA Online Interface. Relevant VTAM applications are: TSO, ROSCOE, IOA VTAM monitor, CICS, IMS/DC, and any VTAM application that supports the IOA Online Facility.