Through data-in-virtual, your program can map a VSAM linear data set to a data space. Use DIV macros to set up the relationship between the object and the data space. Setting up this relationship is called "mapping". In this case, the virtual storage area through which you view the object (called the "window") is in the data space. The STOKEN parameter on the DIV MAP macro identifies the data space.
The task that issues the DIV IDENTIFY owns the pointers and structures associated with the ID that DIV returns. Any program can use DIV IDENTIFY; however, the system checks the authority of programs that try to use subsequent DIV services for the same ID.
For problem-state programs with PSW key 8 - F, data-in-virtual allows only the issuer of the DIV IDENTIFY to use other DIV services for the ID. That means, for example, that if a problem-state program with PSW key 8 issues the DIV IDENTIFY, another problem-state program with PSW key 8 cannot issue DIV MAP for the same ID. The issuer of DIV IDENTIFY can use DIV MAP to map a VSAM linear data set to a data space window, providing the program owns or created the data space.
Your program can map one data-in-virtual object into more than one data space. Or, it can map several data-in-virtual objects within a single data space. In this way, data spaces can provide large reference areas available to your program.