SAS/ACCESS Interface to CA-DATACOM/DB: Reference

Multi-Tasking

The SAS System creates a new task for each window that is opened by each user. If the host option SYNCHIO equals NO (the default for some environments), asynchronous processing can occur. That is, work in multiple windows can be done concurrently.

CA-DATACOM/DB also supports concurrent tasking. The interface view engine uses Option 3 (the most flexible one), described in the chapter called "Extended Programming" in the CA-DATACOM/DB System Programming Guide. When the SAS System creates a new task, the interface view engine also creates a new task to communicate with CA-DATACOM/DB.

At initialization time, CA-DATACOM/DB must know the maximum number of concurrent tasks that a particular address space will have active. Use the DDBTASK system option to specify this number to the interface view engine. The default is 2. The engine will reject attempts to open more than the maximum number of tasks specified and will issue an error message

For a given address space, the CA-DATACOM/DB operator display facility typically shows a given SAS address space as having one user active for CA-DATADICTIONARY communications and one user active for database work. One task is allocated to CA-DATADICTIONARY, and the number of tasks specified in DDBTASK is allocated to database work. For example, suppose you specify DDBTASK equal to 4. The CA-DATACOM/DB operator facility would allocate and display a total of five tasks for your copy of the SAS System.

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