Creating a data space

To create a data space, issue the DSPSERV CREATE macro. MVS™ gives you contiguous 31-bit virtual storage of the size you specify and initializes the storage to hexadecimal zeroes. The entire data space has the storage key that you request, or, by default, the storage key that matches your own PSW key.

On the DSPSERV macro, you are required to specify:

The name of the data space (NAME parameter)
To ask DSPSERV to generate a data space name unique to the address space, use the GENNAME parameter. DSPSERV will return the name it generates at the location you specify on the OUTNAME parameter. See Choosing the name of the data space.
A location where DSPSERV can return the STOKEN of the data space (STOKEN parameter)
DSPSERV CREATE returns a STOKEN that you can use to identify the data space to other DSPSERV services and to the ALESERV and DIV macros.

Other information you might specify on the DSPSERV macro is:

A request for a SCOPE=ALL or SCOPE=COMMON data space. If you don't code SCOPE, the system creates a SCOPE=SINGLE data space. See Scope=single, scope=all, and scope=common data spaces.
The maximum size of the data space and its initial size (BLOCKS parameter). If you do not code BLOCKS, the data space size is determined by defaults set by your installation. In this case, use the NUMBLKS parameter to tell the system where to return the size of the data space. See Specifying the size of the data space.
A location where DSPSERV can return the address (either 0 or 4096) of the first available block of the data space (ORIGIN parameter). See Identifying the origin of the data space.
A request that the system create a data space where disabled programs can access data (DREF parameter). See Creating a data space of DREF storage.
A request that the data space be fetch-protected (FPROT parameter). See Protecting data space storage.
The storage key of the data space (KEY parameter). Use CALLERKEY to specify that the storage key of the data space is to match your PSW key (or take the default for the KEY parameter). See Protecting data space storage.
The TTOKEN of the TCB to which you assign ownership of the data space (TTOKEN parameter). See How SRBs use data spaces.