SNA NRJE User/Programmer Reference Manual (30292-90006)

Chapter 2 39
Getting Started
Planning Jobs
FD Files
FD files are similar to
Infiles in that they may contain the same kind
of information, they are constructed in the same way, and they can be
transmitted without translation. They are referenced directly by means
of ##FD cards in the
Infile . (SeeFigure 2-1).
FD files may reference other FD files. This nesting can be continued up
to 20 levels deep. Figure 2-1 illustrates the relationships among several
card image files that have been merged into a single job stream. The
names of the
Infiles were indicated by the user when submitting the
job. First-level FD files, RED and BLUE, were specified indirectly by
means of records—card images—contained in
Infile A. Two records
within RED point to the two level-two files.
When SNA NRJE processes a SUBMIT command, it opens each Infile
named directly in the command, and each FD file as it is referenced.
The files are opened with the MPE share and read-only file restrictions.
Each file remains open until all of its records have been processed, at
which time it is immediately closed.
NOTE If an Infile or FD file is kept as a numbered file and the record width
is less than 80 bytes, NRJE will transmit the line numbers as part of
the data record.
Figure 2-1 Relationship Among Files in a Job Stream