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Table 2. Functions of 2265 Display Station Keys (Destructive Cursor) (Cont)
Key
No Shift
Shift
ERASE DPl Y (Erase Display)
Erases entire display. Places an SOM symbol in
Same
upper left corner of display (first displayable
character position), and cursor in second char-
acter position.
ERASE EOl
Erases all characters, beginning with position
Same
(Erase to End of Line)
immediately following that in which cursor is
located and continuing to end of that line.
Cursor does not move.
ERASE EOS
Erases all characters, beginning with position
Same
(Erase to End of Screen)
immediately following that in which cursor
is located and continuing to end of screen.
Cursor does not move.
TEST
Isolates 2845 data set and initiates internal
Same
"wrap" test.
TAB
Initiates a search for a colon. Search begins
Same
with position immediately following cursor.
When a colon is detected, cursor is positioned
to character position immediately following
colon. If any character is already being dis-
played in this position, it is replaced by the
cursor. No intervening characters are erased
or modified.
If no colon is detected before end of screen,
cursor is positioned to upper left corner of
display (first displayable character position).
I
f
any character is already being displayed
. in this position, it is replaced by cursor.
Nl symbol has no effect on tab operation.
If no Tab feature is installed, no operation
occurs.
New Line (N L) Symbol
Start of Message (SOM) Symbol
The SOM symbol (
~)
is used to indicate the beginning
The NL symbol
(~
), when displayed on the 2265 screen,
prohibits the transfer of all data displayed between the
of data that is to be transferred from a display buffer to
the I/O channel during a Specific Poll or General Poll
operation. If data is to be transferred during one of these
operations, the SOM symbol must be displayed on the
2265 screen before the data to be transferred. Upon
successful completion of either operation, the SOM symbol
is automatically deleted from the 2265 screen. Deletion
of this symbol signifies to the 2265 operator that the data
has been successfully transferred from the display buffer
and that another message may be entered.
The SOM symbol is made to appear on a 2265 screen
by depressing the START key on the keyboard of the
2265 or by transmitting the code configuration of the
symbol from the I/O channel to the 2265. For additional
information concerning the SOM symbol, refer to the
description of the above operations under "Principles of
Operation" and "2265 Display Station Keyboard Oper-
ations."
NL symbol and the end of the display line containing the
symbol during a Specific Poll or General Poll operation.
The NL symbol may be either keyboard- or program-
inserted; it enables transfer of only a portion or portions
of data displayed on the 2265 screen during either of the
above operations. The effect of depressing the NEW LINE
key is described in Tables 1 and 2.
Check Symbol
The Check symbol ( , ) is used to indicate detection of a
parity (YRC) error in transmission of data to the 2845
display buffer during a Write operation. When a character
with incorrect parity is detected by the 2845 Display
Control during a Write operation, a Check symbol is dis-
played in place of the character in error. The Check
symbol carfruso be displayed by transmission of the code
configuration for the Check symbol from the I/O channel
to the 2265.
Introduction
19
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