Data spaces and hiperspaces are similar in that both are areas of virtual storage that the program can ask the system to create. They differ in the way your program accesses data in the two areas. This difference, and others, are described in other sections. But before you can understand the differences, you need to understand what your program can do with these virtual storage areas.

Under certain conditions, virtual input/output (VIO) can be a better option than a data space or a hiperspace. Choosing VIO instead of a data space or a hiperspace compares data spaces, hiperspaces, and VIO, and presents some trade-offs.