ICEPRMxx members in PARMLIB or the ICEMAC macro can be used to modify the IBM-supplied installation default values for DFSORT. Many of these installation options have an impact on performance, including:

• Storage limits
• Hiperspace, data space, and memory object limits
• Use of system-determined block size
• Reallocation of VIO work data sets
• Use of dynamic allocation for work data sets
• Number of work data sets for dynamic allocation
• Device type for dynamically allocated data sets
• Use of control interval access for VSAM data sets
• Number of I/O buffers to use
• IDRC tape compaction ratio
• Use of VERIFY, EQUALS, ALTSEQ, and LOCALE

Modifications to the installation defaults should be carefully chosen to reflect how you want DFSORT to run at your site. You should only override installation options for which the supplied default values are not acceptable. You can easily change installation options using a START ICEOPT command from the console or in a COMMNDxx member in PARMLIB. For example, to use the installation options specified in an ICEPRM01 member of PARMLIB, type the following at the console:

start iceopt,iceprm=01