October 8, 2009

Default for PL/I AMODE Setting Changing on October 19, 2009

On October 19, 2009, the default setting for AMODE (or addressing mode) will change from 24 to 31 in all PL/I link-edit procs maintained by the NIH Data Center. AMODE controls the range of storage addressing the program uses.

On the mainframe, an area of memory can be located either above or below the 16 megabyte line. The term "the 16 megabyte line" means the point at which the memory addresses require four bytes of storage to hold them rather than three bytes.

There are two AMODE values:

• AMODE(24) indicates 24-bit (three-byte) addressing - memory below the 16 megabyte line


• AMODE(31) indicates 31-bit (four-byte) addressing - memory above and below the line

The AMODE=31 default setting will take effect when the program is link-edited.

If you still have a need to use AMODE=24 after this date, you can override the default setting in your JCL by including the AMODE=24 parameter.

Need help or have questions?

If you need help or have any questions regarding the change for the PL/I AMODE parameter, just submit a service request via the NIH Help Desk’s website (http://ithelpdesk.nih.gov/support/) or give them a call at 301-496-HELP (301-496-4357), 866-319-4357 (toll free), or 301-496-8294 (TTY).