Both used to read sequentila file.

Read work file 1:

1. is a processing loop strating like:

Read work file 1 file1

---

--

--

end- work.

Here ---> file 1 is file name here and 1 is arbitary file

number which is translated into dataset names CMwk01 in jcl.

read work file once:

1. Reads only one reacord is to be read.

2. there is no processing loop

eg. Read work file once