GIMDTS first checks for the required data sets, opens the SYSUT1 and SYSUT2 data sets, and makes sure these data sets have the correct attributes. If necessary, GIMDTS changes the RECFM value of the SYSUT2 data set to FB and the BLKSIZE value to 3200. Next, GIMDTS reads records from the SYSUT1 data set and transforms the data.
After processing the data, GIMDTS writes the output records to the SYSUT2 data set. GIMDTS also issues messages to SYSPRINT indicating the input data set, the output data set, and the return code. If any errors occur during processing, GIMDTS issues messages describing the errors and stops processing. If an abend occurs, normal system abend processing is done.
If SYSUT1 is already fixed-block with LRECL=80 and the data has no "++" characters in columns 1 and 2, then the data needs no transformation and is simply copied from SYSUT1 to SYSUT2.