Enter Mode (E) - IBM 3741 Data Station Reference Manual

Enter Mode (E)
Enter mode is the most basic mode of operation. Enter
mode can be selected from the index track only; a mode
selection (M) error results if enter mode is selected from
any other position on the disk. Enter mode is used to
write new information on the disk. To select the enter
mode, press FUNCT SEL lower and then press ENTER.
As the operator keys a record, the data is stored in the
current record buffer until the record is completed. When
a record advance occurs, the completed record is trans-
ferred to the previous record buffer. While the next
record is being keyed into the current record buffer, the
previous record is written on the disk.
The data flow is summarized in Figure 9. When enter
mode is selected, the disk is positioned at BOE; the
current record buffer and the previous record buffer are
set to blanks. The station is then ready to accept data
keyed into the current record buffer.
As data is keyed, it is
stored in the current
record buffer and .....
f-----
displayed on the
screen.
Keyboard
.-At record advance,
the data is moved
[f
to the previous
record buffer and
written on the disk.
The current record
is filled with blanks
to allow the operator
to key the
next data record.
•
Figure 9. Data Flow for Enter Mode
12
Display
01
•
0
Disk
J]
Alternate Record Advance in Enter Mode
An alternate method of record advance in enter' mode can
be selected by pressing FUNCT SEL lower and then R. A
dash will appear in position 39 in the status line. The
record advance function in enter mode is changed so that
all fields that follow the position of the cursor at the time
of record advance are not executed in contrast to these
fields being executed.in normal ent'er mode. The alternate
record advance.function has this .advantage: When the
REC ADV key is pressed, the record is always written on
the disk exactly as the operator. sees it on. the display (no
automatic duplicate or skip fields are executed). The
normal record advance may cause changes in automatic
duplicate and skip fields that are beyond.the cursor posi-
tion at the time of record advance.
To return the machine to the normal enter mode, press
FUNCT SEL lower and K. Inserting a.disk or turning the
power on will also establish the normal mode.
Right Adjust Fields
Programmed right adjust fields allow data entered into the
current field to be moved to the right field .boundary by
pressing the RIGHT ADJUST key. Right adjust fields must
be at least two characters long and can be as long as a whole
record. In enter mode, the RIGHT ADJUST key is used to
exit a right adjust field. When the RIGHT ADJUST key is
pressed, the 3741 shifts the characters previously entered
in the field (up to the cursor position) to the right field
boundary. Fill characters are inserted to the left of the
first keyed character as required. The fill character used
depends on the field definition character used for the field.
See
Right Adjust Fields
in Chapter 3.
Pressing the RIGHT ADJUST key in the first position of a
right adjust field enters fill characters into the entire field.
The dash (-) key, when used in a right adjust field that is
programmed for numeric shift, gives a negative value to
the number and then causes the field to be exited. The
units (rightmost) position of the negative number contains
an alpha equivalent if the digit is 1 through 9 (1=J, 2=K,
3=L, 4=M, 5=N, 6=0, 7=P, 8=0, 9=R) or the hex code DO
if the digit is O. The numbers in the other positions of the
right adjust field have their numeric value. For example, if
21 is entered in a five-position, zero fill, right adjust field
and the dash key is pressed, the field will contain 0002J
(negative 21).
Note:
Performing a character advance or field advance
will cause the right adjust fieJd to be exited in enter mode.