Chapter 5. Programming Information; Program Coding; Loading A Program; Selecting A Program - IBM 3742 Reference Manual

Chapter 5. Programming Information
Programs similar to those used on the IBM 029 Card Punch
can be written to control data set format. Programs are
entered on disk using the same procedures used to enter
data. Normally, programs are stored in a different data set
than data. Programs are loaded into the program buffer
from the current record buffer. Programs can be entered
into the current record buffer from either the keyboard or
from disk.
The 3741 and the 3742 with the 128 feature provide
storage for up to ten different programs, numbered 1
through 9 and A. The 3742 stores up to six programs,
numbered 1 through 6. The number of the program being
used is displayed in the status line. When operating under
manual control, program level 0 is displayed in the status
line.
PROGRAM CODING
The first character in each field, called a field definition
character, defines the type of field and indicates where each
field begins. The field definition character of the field
being processed is displayed. If a field is more than one
position long, the first definition character is followed by
the appropriate field continuation characters.
An E character normally follows the last program definition
or continuation character. Programs that are 80 characters
long for the 3742 or that are 128 characters long for the
3741 or the 3742 with the 128 featu re do not use the E
character.
When the cursor reaches a position containing an E charac-
ter in the program, a record advance occurs if the AUTO
R EC ADV switch is on. If this switch is off, the following
characters in the status line are changed: the field definition
character is set to E, the field continuation character is
blanked, and the position indicator is set to 00 on the 3742
and 000 on the 3741 or 3742 with the 128 feature. Keying
in position 00 or 000 causes a Terror.
For a list of field definition characters and their meanings,
see Figure 19. For other character code meanings, see
Figure 20.
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LOADING A PROGRAM
To load a program:
1.
2.
Press PROG LOAD.
Press the key indicating the program buffer where
the program is to be loaded. This can be any num-
ber 1 through 6 on the 3742 or any number 1 through
9 or A on the 3741 or the 3742 with 128 feature.
The contents of the current record buffer are then loaded
into the selected program buffer; then the current record
buffer is filled with blanks, and program level 0 is selected.
To cancel a program load function, press RESET. An M
error is posted in verify or field correct modes.
SELECTING A PROGRAM
To select a program for data entry, press SEL PROG and
the numeric key corresponding to the number of the pro-
gram buffer containing the program you want to use. This
can be any number 0 through 9 or A on the 3741 or the
3742 with 128 feature, 'or any number 0 through 6 on the
3742. Pressing any key other than a valid program buffer
number gives a P error.
In order to select a program, both the program currently
being used and the program being selected must be in the
first position on a field or the end of a record. If the current
program is not at the start of a field or the end of a record,
an 0 error is displayed; if the program to be selected is not
at the start of a field or the end of a record, a P error is
displayed. The program in control does not change. If a
program is selected at end of record condition, a record
advance function occurs after the program has been
selected.