Input
Section
An
input machine
is
any machine
that
provides for entry
of
outside data (infor-
mation) into the host system. This definition can be used
to
determine
if
a
machine
is
part
of
the input section
of
a data processing system. Input machines
may be located
at
the host system site or at remote locations where they com-
municate with the host system over telephone lines.
Most
of
the data needed
to
perform a job
is
produced
by
people.
As
a result, it
is
handwritten
or
typed
on
one kind
of
form or another. A host system cannot
process this data. These forms are the source
of
the input data to be entered into
the host system. Thus, the data at this point
is
called source data.
Part
of
the
job
of
the machines in the input section
of
a data processing system
is
the translation
of
the source data into a form
that
the host system can under-
stand. These machines translate the source data and record it in the host system's
language; also, and perhaps most important, they enter it into the data processing
system.
As
you type from the source documents,
you
and your 3270 display
station will be performing this type
of
work. Note that the selector light pen,
operator identification card reader, and magnetic slot reader are also input devices
which assist you in communicating with the host system.
The importance
of
the input section in a data processing system cannot
be
stressed
enough. You may be the best typist in the world, but,
if
you are given inaccurate
information
to
type, your completed typing will
not
be
of
much value. The same
is
true
of
any data processing system. The best host system in the world can pro-
duce results
(output)
of
value only with accurate input data.
The machines
that
make up the input section, though small compared with some
of
those in the processing section,
are
vital
to
the success
of
the data processing
system. Keypunches and card readers, typewriter terminals, and display stations
are some types
of
input machines.
Processing Section
The host system site,
as
you might guess,
is
where the host system
is
located.
Once the system has all the information it needs for the intended job, the
required work must be performed. This
is
done at the host system site
by
the
group
of
machines
that
make up the processing section
of
a data processing
system.
Several types
of
machines at the host system site process the data. Working
together, they are used to sort the data, test it, perform computations on it,
and otherwise use it to accomplish the assigned job.
Note
that
we
said these machines are used to process data. The host system pro-
gram uses the host system's capabilities.
Although a
host
system
is
a group
of
machines capable
of
doing many jobs,
its actions must be directed. The machines and the program are two separate
things; however, they must work together
to
form an operating data processing
system.
One can do nothing without the other. The program operates within
the host system and directs the machines in the host system to accomplish the
assigned job.
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