Accessing hiperspaces

The HSPSERV macro service controls the use of a hiperspace. HSPSERV requires that the program that is accessing the hiperspace specify the STOKEN of the hiperspace. The program could have received the STOKEN from DSPSERV or received it from another program. HSPSERV considers the following factors before it allows a program to access a hiperspace:

The authority of the caller
The type of hiperspace: non-shared standard, shared standard, or ESO
Whether the caller is in cross memory mode
Whether the caller gives an access list entry token (ALET) for the hiperspace to HSPSERV
On a write operation, whether the PSW key of the accessing program matches the storage key of the hiperspace, or is zero.

When you access hiperspaces, you are not required to use an ALET. However, there are benefits to using ALETs with hiperspaces. By obtaining an ALET, a program builds a connection between the program and a hiperspace. When the program supplies the ALET on HSPSERV, the program can:

Access some hiperspaces that it could not otherwise access. See How problem state programs with PSW key 8 through F use a hiperspace and How supervisor state or PSW key 0 through 7 programs use hiperspaces.
Take advantage of faster or more efficient data transfer. See Obtaining improved data transfer to and from a hiperspace.

A program has two ways to obtain an ALET:

From another program, as a passed parameter
From the ALESERV ADD macro, if the program has the STOKEN for the hiperspace.

The decisions of whether to create a non-shared standard or shared standard hiperspace and whether to obtain an ALET depend on how you plan to share the data in the space. The sections that follow help you understand which hiperspaces HSPSERV allows problem state and supervisor state programs to access, and also the benefits of having an ALET. Obtaining an ALET for a hiperspace describes how to obtain an ALET.