Users can recall migrated files without explicitly invoking HSMS.
As soon as an access attempt is made, the Data Management System (DMS) of BS2000 determines on the basis of the catalog entry that the data belonging to a migrated file is not available on the processing level.
If a user or a user program attempts read access to a migrated file (OPEN modes INPUT, INOUT, but also UPDATE, REVERSE and EXTEND), the data of that file is automatically (implicitly) recalled to the processing level.
If a user wants only write access to the file (OPEN mode OUTPUT or OUTIN), all data of the file is to be overwritten, i.e. no previous recall is necessary.
In the case of an implicit recall, the data of the file is fetched from a save file on the storage level entered in the catalog.
The procedure for file access via SECURE-RESOURCE-ALLOCATION is somewhat different. This BS2000 command enables you to announce the upcoming access to one or more files. As also in conjunction with devices and exclusively occupied volumes (e.g. magnetic tape cartridges), in this case the command is also used to make all the required resources available (in this case files and their data), i.e. if necessary to initiate a recall.