Keyboard Fu,nctions ." System Overview This section describes the of the 3270 keyboard which are unique to , DISPLAY EDITING SYSTEM for C>MS. Users should also acquaint themselves ' with the 'OPERATOR'S GUIDE for IBM 3270 INFORMATION DISPLAY SYSTEM' 16
(GA27-2742). " .' ". , . .PAl
.PA2
.PA3
Depression of this key will cause 'cp' mode to be entered and
a "CP READ" status will be displayed. While in this environ­
ment, any 'CP' commands may be issued. To return to
EDGAR from the 'CP' environment, issue the 'CP' command, "BEGIN". Depression of PA 2 will cause the CMS SUBSET environment
to be entered and a "RUNNING" status to be displayed.
While in the CMS SUBSET environment, any CMS commands
which run in the transient area may be issued. For example: ACCESS CP DISK ERASE EXEC LlSTFILE PRINT PUNCH QUERY READCARD RENAME
RETURN
SET
STATE
TYPE
To return to EDGAR from the CMS SUBSET environment,
issue the CMS SUBSET command, "RETURN". Depression of the PA 3 key (available only on "data-entry" type keyboards) is considered invalid by EDGAR and will
cause the "input inhibited" indicator to appear, the keyboard
to "lock," and the audible alarm to sound (if this feature is
installed).
NOTE: Depression of any PA key does not cause transmission of data to the
computer. Hence, alterations made to the screen before depressing a PA key
and after depressing ENTER or a Program Function key, will be lost. • FIELD MARK Depression of this key inserts a logical tab character into the
data stream. This is functionally equivalent to entering the
character defined by the T ABCHR control statement. (See Section III, System Overview, Initialization and Termina­
tion). Logical tabs are useful as a means of shifting data to a
specified data column without causing an I/O interrupt for
each "tab" operation. When using logical tabs the data on
the screen is not rewritten and will not appear to be shifted
until an "ENTER" key is depressed. At that time, the data
file is updated, the I/O virtual screen is rebuilt and, when it i! displayed will reflect the changes to the data. • DUP The DUP key is useful in conjuction with a logical tab opera­
tion. It indicates that the rest of the data read as part of this
screen field is to be ignored. When used in conjuction with
the overlay facility of logical tab it allows the user to indicatt: the end of the new "typed-in" data. For example if the data
appears as

.ENTER
.CLEAR ABC DEF GHI and the user overlays that with
;bc*DEF GHI where ';' is a FIELD MARK, '*' is a DUP
l the upper case is
residual data and the lower case that which the user types in;
the result will be
ABC BCF GHI This example assumes T ABDEF is set to a "null string" and
that the' A', the '0', and the 'G' are in the "tab stop" col­
umns.
Depressing the ENTER key indicates that the I/O virtual
screen is to be passed to the Display Processor (see Section
III, System Overview, System Flow). It is not until the
ENTER key has been depressed, either at the physical display
device itself or simulated via SOS, that the screen is analyzed
and any resultant action taken.
When depressed on the physical display device once, the
CLEAR key causes the physical screen to be rebuilt as it
appeared the last time an interrupt causing key (PF keys or
ENTER key) was depressed. In all other cases, the CLEAR
key causes the I/O virtual screen to be rebuilt as it appeared
after the ENTER key was last depressed, and the CMS console
stack to be purged.
System Overview 17