DFU

DFU = Data File Utility.

DFU can be used

• by programmers to update data base files on the fly without writing programs
• by programmers to set some very simple "programs" to do some very simple functions with some data base file
• by data entry personnel to key in data to some data base file

We can use it to create a format or simplistic "program" that will let us update a file one record at a time, or with option 5 from STRDFU, we specify the physical or logical file and member (or *FIRST) then the 400 will setup a dummy set of DFU specifications on the fly, to let us update that file.

The file layout has to exist before we can access it vie DFU, while we can use DFU to add records.

With DFU, we can access a file to

• add records
  • If we have an old IBM Keyboard with the DUP key, then when we are on any screen but the first, in a series of screens of records being added, pressing the DUP key in a field, causes the contents to be duplicated from the previous record entered for that field
• delete records
• change records
• display records
  • the roll keys (page up down) take us through the file of records
• print records

The command keys use a different set of rules for DFU on old S/36 as opposed to on OS/400