April 27, 1981 USING PROGRAM FUNCTION KEYS You can enhance the use of the CMS editor on a 3270 by setting the
proqram function (PF) keys on your terminal to correspond to some of the
more frequently used EDIT subcommands, such as UP, DOWN, SCROLL, FILE, SAVE, and so on. You can also set a program function key to contain a
line of data, so that if you are creating a file that has many duplicate
lines in it, you can use the PF key instead of having to key in the
entire line each time. PF keys cannot, however, contain lowercase
character strinqs. You can set a program function key whi Ie you are in edit mode either
by using the PA1 key --REQ key on a 3278 Model 2A to enter the CP environment or by using the #CP function. USING THE EDITOR IN LINE MODE The editor's display mode is the most common format of operation on a
3270. There are, however, instances when it is not possible or not
desirable to use the editor in display mode. For these instances, you
should use the line mode of operation, which is the equivalent to using
a typewriter terminal. When you use line mode, each EDIT subcommand you
enter, and the response (if you have verification on), is displayed, a
line at a time, on the screen in the output display area. There is no
full screen display of the file. You need only be concerned with using line mode if you are connected
to VM/370 by a remote 3270 line, or if you are editing a file from
within an EXEC and you want to control the screen display. Although it
is possible to use the editor in line mode on a local 3270, it is rarely
necessary for normal editinq purposes. When you invoke the editor from a remote 3270, you are placed in line
mode by the editor. The advantage of using the 3270 in line mode
(particularly on a remote editor) is that the editor can respond more
quickly to display requests. When you use display mode, the editor has
to write out the entire output display area when you move the current
line pointer; in line mode, it has only to write a single line.
If you want to use display mode, you enter the EDIT subcommand:
format display
The editor begins operating in display mode, and you can use the special
editing functions available in display mode.
However, when you are using a remote 3270 in display mode, and you
enter the INPUT subcommand to begin entering input lines, the screen is
cleared, and your input lines are displayed as if you were in line mode,
beginning at the top of the screen. When you enter a null line to return
to edit mode, the editor returns to a full screen display. You can resume editing in line mode by using the subcommand:
forma t line
348 IBM VM/370 CMS User's Guide

March 30, 1979 FrQ.! g1! If you invoke the editor from an EXEC, but you do not want the screen
cleared when the editor gets control, you can specify the NQDISP option
on the EDIT command line:
edit test file (nodisp
This places the 3270 in line mode, so that the lines already on the
screen are not erased.
The 3270 remains in line mode for the remainder of the edit session,
and you cannot use the FORMAT subcommand to place it in display mode. USING SPECIAL CHARACTERS ON A 3270 There are two special characters available on a typewriter terminal
whose functions have no meaning on a display terminal. They are the tab
character (X'05') and the backspace character (X'16'). For most file
creation and editing purposes, you will probably not need to use the
backspace, but many CMS filetypes use tab settings to set up the proper
column alignment in files. There are two methods you can use to enter
any special character on a 3270 (including tabs), and an additional method of using tabs, which involves setting a program function key. In
addition, the tab character can also be set via the CP command TERMINj1 I!BCHAR. To enter any special character (a backspace is used in this example)
you can either: 1. Enter another character at the appropriate place in the and then use the ALTER subcommand to alter that character to the
hexadecimal value of the character you want to represent (a
backspace character is a X'16'). For example: input ABC»> alter > 16 1-*:-" When you enter backspaces and overstrike characters on a 3270, however, the characters and backspaces each occupy character
positions, so that a single compound character occupies three
character positions on the screene If the image setting is CANON, and you want to use the backspace to enter compound characters, you
must not enter the backspace character first.
2. Before you begin to create the file, use the CMS SET command to
define some other character as the backspace character:
set input> 16 CMS then translates all occurrences of the character> to X'16'. If you need to correct a line that contains backspaces, you can
reverse the above sequence; alter the X'16' characters to asterisks and
enter the CHANGE subcommand. !Qf I!B You can set up a program function key to operate like a tab key on a
typewriter terminal. You must use the CP SET command as follows: SET PFnn TAB n1 n2 • • • nn
Appendix C: considerations for 3270 Display Terminal Users 349