With ACS (Alias Catalog Service) it is possible to access files and JVs under names which are, within certain limits, freely selectable. Users thus have the option of defining aliases for the files/JVs they require and of storing them in special catalogs, the alias catalogs, together with the assignment to the real file/JV. Only the alias need then be specified when processing files/JVs. Alias catalogs are managed on a task-local basis.
Overview of ACS functions and their advantages
The Alias Catalog Service (ACS) includes three basic functions:
Alias definition
Catalog ID insertion for temporary SPOOL files
Prefix insertion
Alias definition
ACS commands can be used to define aliases for files/JVs within a task. These definitions are placed in a (temporary) catalog known as the alias catalog and can be optionally saved in permanent files and subsequently reloaded into the alias catalog (even by other tasks) if required. When a file/JV is accessed, the actual name is substituted for the alias. Alias definitions are task-local. The alias catalog is deleted on completion of the task.
This function provides independent access to software products without regard to their versions or computer center IDs. The information required for this purpose, however, must be supplied by systems support in the form of an alias catalog system file. Users are thus free to define file/JV names, user IDs, and catalog IDs without the constraints of computer center conventions and version changes; their procedures will still be portable. Files/JVs that belong to unbundled software products can always be addressed with the same alias in an alias catalog regardless of versions and computer center IDs.
Catalog ID insertion for temporary SPOOL files
It can be used to define a system-wide catalog ID (catid) for the temporary files/JVs generated by the SPOOL task. Such files/JVs are then no longer stored on the default pubset of the user task. This function is only relevant for the ACS administrator.
As far as nonprivileged users are concerned, this function is only evident in the output fields of the SHOW-FILE-ATTRIBUTES command.
Prefix insertion
This function can be used within a task to define a specific prefix that is to be implicitly placed before the file name according to appropriate conventions whenever a file name is entered.
The function of prefix insertion offers a convenient way of structuring file/JV names within a user ID. Files can be grouped together from a functional point of view. This allows users to set up a form of sub-catalog within their user ID, for use as a local working environment. This allows the user to set up a form of subcatalog within his/her user ID for use as a local working environment. Under a shared user ID, files/JVs can be addressed under a prefix which designates the name, product or version.