IBM 1130 User Manual page 88

Section
Subsections Page
15
10
I
40 01
Need for Inquiry into Your File
In some cases it is very desirable to be able to look
into your data file to get certain current information:
number of pieces of item number 170653 on hand,
year-to-date gross pay of man number 8091, etc.
When your data file is in the form of a card deck,
this is relatively easy, since you merely find the
right card, interpret it, and read the data, much as
you would any other hard-copy file - index cards,
ledger sheets, etc.
People are accustomed to doing- this, and often
resist the change to disk-resident files because they
cannot "see" what is on the disk.
It
is true that data written on the disk is somewhat
less tangible than if it were on a deck of cards, but
this is not the overriding consideration it is made
out to be.
True, it takes a special program or subprogram
to read and display data on a disk, so demands for
inquiry do add a few points to the "card file" side of
the balance. However, a properly designed system
can lessen or eliminate these points entirely.
If someone within your company requires, say,
the current status of inventory, it may be possible
to replace his 5" x 8" card file with a daily listing
of stock status, or a weekly listing with daily up-
dates. If he insists on immediate response to
up-to-the-minute status, the programmer can build
an inquiry subroutine into every program, calling it
only when some console switch is turned on:'
CALL DATSW(7, MM)
GO TO (9,10), MM
9 CALL INQUR
10 CONTINUE
These four statements would be placed at a con-
venient spot in every program. Whenever anyone
wanted to inquire of the disk, he would turn on
switch 7. The subroutine INQUR would soon be
called, and probably request that a part number be
entered through the console keyboard. After the
requested information was looked up on the disk, it
would be typed on the console printer, and the main
program would continue.
Large demands for inquiry sometime s make the
use of card files appear more attractive than disk
files, but proper systems design can often reduce
the importance of this factor. In fact, inquiry into
a disk-resident file is often a plus factor, since the
data obtained would have an up-to-the-minute status.