Use the MDSJST macro to read, write, release, or checkpoint a job's job summary table (JST) in code that runs under the MDS (SETUP) FCT. This macro must be issued before each MDSJGET macro. On return, the address of the JST header is in register 1. JST header refers to the first JST buffer, unless JGETEOD=DYNALOC was specified. In this case, JST header refers to the first buffer for the last dynamic allocation of the requested step.