Preallocate ISPF temporary data sets to VIO

ISPF uses temporary data sets to generate JCL or utility control statements or to generate listings. To preallocate these data sets to VIO, include the DD statements in Figure 1 in the TSO LOGON procedure.

Preallocation of these data sets to VIO is not mandatory; ISPF automatically allocates them to real data sets if required. However, preallocation is recommended, because it reduces overhead and eliminates potential problems from insufficient space.

Figure 1. DD statements to preallocate data sets

//ISPCTL0  DD DISP=NEW,UNIT=VIO,SPACE=(CYL,(1,1)),
//            DCB=(LRECL=80,BLKSIZE=800,RECFM=FB)

//ISPCTL1  DD DISP=NEW,UNIT=VIO,SPACE=(CYL,(1,1)),
//            DCB=(LRECL=80,BLKSIZE=800,RECFM=FB)

⋮
//ISPCTLW  DD DISP=NEW,UNIT=VIO,SPACE=(CYL,(1,1)),
//            DCB=(LRECL=80,BLKSIZE=800,RECFM=FB)


//* In this section of JCL, there is one DD for each screen
//* defined, based on the value of keyword MAXIMUM_NUMBER_OF_
//*  SPLIT_SCREENS in the configuration table.
//* The DD name is in the form ISPCTLx, where x can be
//* 1-9, A-W.  For example, if the keyword value = 8, only
//* ISPCTL1 to ISPCTL8 need to be coded.
//* ISPCTL0 is a special case, used only by Edit for the Submit
//* command.

//ISPWRK1  DD DISP=NEW,UNIT=VIO,SPACE=(CYL,(1,1)),
//            DCB=(LRECL=256,BLKSIZE=2560,RECFM=FB)

//ISPWRK2  DD DISP=NEW,UNIT=VIO,SPACE=(CYL,(1,1)),
//            DCB=(LRECL=256,BLKSIZE=2560,RECFM=FB)

⋮
//ISPWRKW  DD DISP=NEW,UNIT=VIO,SPACE=(CYL,(1,1)),
//            DCB=(LRECL=256,BLKSIZE=2560,RECFM=FB)

//* In this section of JCL, there is one DD for each screen
//* defined, based on the value of keyword MAXIMUM_NUMBER_OF_
//* SPLIT_SCREENS in the configuration table.
//* The DD name is in the form ISPWRKx, where x can be
//* 1-9, A-W.  For example, if the value of the keyword = 8,
//* only ISPWRK1 to ISPWRK8 need to be coded.

//ISPLST1  DD DISP=NEW,UNIT=VIO,SPACE=(CYL,(1,1)),
//            DCB=(LRECL=121,BLKSIZE=1210,RECFM=FBA)

//ISPLST2  DD DISP=NEW,UNIT=VIO,SPACE=(CYL,(1,1)),
//            DCB=(LRECL=121,BLKSIZE=1210,RECFM=FBA)

⋮
//ISPLSTW  DD DISP=NEW,UNIT=VIO,SPACE=(CYL,(1,1)),
//            DCB=(LRECL=121,BLKSIZE=1210,RECFM=FBA)

//* In this section of JCL, there is one DD for each screen
//* defined, based on the value of keyword MAXIMUM_NUMBER_OF_
//* SPLIT_SCREENS in the configuration table.
//* The DD name is in the form ISPLSTx, where x can be
//* 1-9, A-W.  For example, if the value of the keyword = 8,
//* only ISPLST1 to ISPLST8 need to be coded.

Note:

When allocating to VIO, make sure that enough auxiliary storage is dedicated to VIO so that system availability is not affected.
Use of the BUFNO parameter on allocation of ISPF libraries is not supported.
The ISPF temporary data set default names associated with the ISPCTLx are SPFTEMPx.CNTL, respectively, where x= value 0-9, A-W.
The ISPF temporary data set default names associated with the ISPWRKx are SPFTEMPx.WORK, respectively, where x= value 1-9, A-W.
The ISPF temporary data set default names associated with the ISPLSTx are SPFTEMPx.LIST, respectively, where x= value 1-9, A-W.
The ddnames ISPWRKx are used by ISPF for file tailoring services with ISPFILE allocated to a PDS. The ddnames ISPLSTx are used for generated listings.
The ddname ISPCTL0 is used with the edit SUBMIT command. The ddnames ISPCTLx are used with ISPF compress (both interactive and the LMCOMP service) and ISPF background (option 5), and for processing the file tailoring service FTOPEN TEMP.
ISPCTL1 is a required ddname when using SCLM. The data set should be allocated as an ISPF temporary data set for SCLM foreground processing and should be added to the FLMLIBS skeleton for batch processing.
ISPF does not support multivolume temporary data sets. If DFSMS is installed, temporary data sets dynamically allocated by ISPF must be assigned a data class with a volume count of one. This can be controlled in the ACS routines by testing the execution mode (&XMODE) for a value of TSO.
If you have dialogs that need to edit or browse temporary data sets, use the LMINIT service to associate a DATAID with ddname ZTEMPN and invoke edit or browse using the DATAID parameter. For more information, refer to the BROWSE and EDIT services in the z/OS ISPF Services Guide.