Through data-in-virtual, a program can map a VSAM linear data set residing on DASD to a hiperspace. The program uses the read and write operations of the HSPSERV macro to transfer data between the address space buffer area and the hiperspace window. It is recommended that you obtain the ALET for the hiperspace and use the HSPALET parameter on HSPSERV to get faster data transfer to and from expanded storage.

When a program maps a data-in-virtual object to a non-shared or shared standard hiperspace, the system does not bring the data physically into the hiperspace; it reads the data into the address space buffer when the program uses HSPSERV SREAD for the area that contains the data.

Your program can map a single data-in-virtual object to several hiperspaces. Or, it can map several data-in-virtual objects to one hiperspace.