LSSBs are service-specific background storage areas which are used to forward data between program units within a service. In standalone applications their contents are stored externally in the KDCFILE, see "Storage location for user data" (KDCS storage areas in openUTM). While openUTM automatically makes the communication area available for each program unit and then saves it, the LSSB is only accessed when necessary. It is therefore particularly useful for data which is accessed for reading only or if multiple program units are present which do not require the data between the point when the data is written and the time it is read.
For example, you can use LSSBs in the following cases:
creation of a ”browse function" for dialog outputs
"temporary" data storage
You can use the SPUT call to write to a LSSB. To do this, enter the name of the area you want to write to. This name is only valid for the local service; if two services have the same name, then the names designate two different LSSBs. The LSSB is set up on the first write access within a service. Here the programmer defines the length of the LSSB. An LSSB can have a maximum length of 32767 bytes.
You use the SGET call to read from the area. If the storage is not required after the SGET call, it can be simultaneously released. You can also use the SREL call to release an LSSB. As soon as the associated services has terminated, any unreleased LSSBs are released.
The maximum number of LSSBs that you can create within a service is determined when the application is generated (MAX statement, LSSBS operand, see also the openUTM manual “Generating Applications”).
Unix, Linux and Windows systems
In UTM cluster applications LSSB contents are stored externally in the cluster page pool, see "Storage location for user data" (KDCS storage areas in openUTM).