The Disk As Seen By The Fortran Programmer - IBM 1130 User Manual

THE DISK AS SEEN BY THE FORTRAN
PROGRAMMER
When programming in 1130 FORTRAN, the disk
appears to be an entirely different device than the
one just described. It consists of a data area which
can be subdivided into any number of files, whose
physical size, symbolic names, and symbolic num-
bers have been determined by you.
You may further subdivide each file into some
number of equal-size blocks known as records. You
choose the size of the record, and each record has
a symbolic record number, starting with 1.
Section Subsections
Page
80
20
I
00
01
Within the record you can place fields, which may
be real, decimal, or integer numbers, oralphameric
data.
This is an extremely flexible system, as opposed
to the rigid subdivisions and addresses of the actual
hardware. It is still one and the same disk, how-
ever, and you must have a good knowledge of both
systems to use the disk effectively. This section
presents the basic guidelines by which you can relate
these seemingly diverse systems:
The physical, or hardware, system
The logical, symbolic, or software system