IBM 1130 User Manual page 129

Data Sequence
Data sequence is most critical for those files that
work with source documents. Card punching, term-
inaloperations
3
etc., being manual operations, are
subject to the greatest variation in rate of production.
Anything that simplifies these functions tends to en-
sure a faster and more accurate operation. The fol-
lowing are points to bear in mind:
• Recording of data in the same order as that in
which it is normally read. If the data sequence is
considerably different from that on the source docu-
ment, it may be necessary to redesign the source
document and retrain personnel. If the file is to be
used as input to a serial I/O unit, such as disk to
card, the sequence is dictated mainly by the se-
quence desired on the output unit.
• Location of like fields in the same relative
record pos itions in files that work together. This
Section Subsections Page
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ensures that sorting and controlling can be ac-
complished if the file is contained in cards; it also
facilitates programming.
01
• Placement of sorting fields adjacent to one
another, with the minor code on the right and each
progressively higher code to the left. Although sort
programs can operate on multiple-control fields,
time is used to extract and combine fields into a
single key.
• Compatibility with computer characteristics
so that data sequence does not affect processing
speed.
• Arrangement of alphabetic/alphameric data in
one area of the record. This facilitates handling of
data, particularly in fixed-word-length machines,
such as the 1130, and permits minimum core and
media requirements.
• Adherence to requirements of programming
systems.