RE: Display Files in Cobol/400

["Fisher, Don" <Dfisher@xxxxxxxxxxxxxxxxx>]

I don't recall all the issues I had.  Some may have resulted from my own
ignorance at the time.  I was learning COBOL on the 400 while doing a
project with no help from my co-workers.  You see, they were all RPG people
and I was fresh out of college with my mainframe COBOL knowledge.

One particularly vexing issue had to do with display file formats being
overlapped in memory.  When reading a format record, be it a subfile record
or something else, any other display file information in the buffer was
replaced by the information from the format just read.  In the case of a
standard subfile screen with a header, subfile, and footer format, the
header information had to be saved before the subfile records could be
processed or the header information would look like junk when redisplayed.
Either that or cause a decimal data error.

Another distinction involved how COBOL differentiates between input and
output buffers.  One had to be sure to populate the output buffer for the
information to be displayed and to retrieve information from the input
buffer.

Donald R. Fisher, III
Project Manager
The Roomstore Furniture Company
(804) 784-7600 ext. 2124
DFisher@roomstoreeast.com

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I don't recall significant differences (in degree of difficulty, that is;
naturally MAJOR differences simply due to language).
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