SAS 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 section called "Extended
Programming" in the
CA-Datacom/DB
System Programming Guide. When SAS 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 has active. Use the DDBTASK system option to specify
this number to the interface view engine. The default is 2. The engine rejects attempts
to open more than the maximum number of tasks specified and issues
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 SAS.