Joined: 14 Jan 2008 Posts: 2504 Location: Atlanta, Georgia, USA
A DSECT is referred to as a "DUMMY SECTION" and takes up no storage until addressability has been established. After that, you can issue instructions related to this DSECT.
IE: ABC DSECT
USING *,Rx INFORM ASSEMBLER
Rx (x usually represents 2-12) is the register which contains the storage-address which maps to the DSECT. Unless you know what you're doing, stay away from R0, R1, R13, R14 and R15 as a DSECT base-register.
A COBOL LINKAGE SECTION "01" level is similar to a DSECT, for example, like DFHCOMMAREA in CICS.
COBOL automatically maps the storage (establishes addressability) to DFHCOMMAREA when EIBCALEN is greater than ZERO.