IBM 1130 User Manual page 590

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Use of File Organization

Is it possible to keep mulitple copies of your files,

each in the sequence of a report to be produced?

so, you can avoid sorting.

not, however, as

is likely with moderate to large files, the impor-

tance of your file organization scheme emerges.

Pure Sequential

An answer for files organized in a pure sequential

manner is to maintain multiple copies on multiple

disk cartridges. This eliminates sorting but may

cause problems in processing.

(See Figure 75.4.)

Generally, with pure sequential files that are too

large for multiple copies, the solution is offline

Indexed Sequential

Is it possible to keep multiple copies of your index,

with each index in the sequence of a report to be

produced? Since your index is considerably smaller

than your file, this may be the ideal solution.

essing against the file would be random.

ure 75.5.) Again,

this solution cannot be used,

you can still sort offline.

this case your files are usually organized in a

sequence that does not relate to a report. The

transactions (say, cards containing only control

keys) must be sequenced appropriately; a sort is

necessary. Hence, the only way to avoid sorting

using your 1130 is to sort offline.

in part number

for sales report

sequence, for inventory

Figure 75.4. Same data in two files, but in different sequence

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