Unlike the F keys, pressing a K key does not trigger any transfer of the modified data from the screen to EDT. All input in the screen is therefore lost.
[K1] Terminating EDT
Pressing [K1] requests the termination of EDT. Unlike termination with @HALT, a confirmation query is issued in the work window's message line even if the work files do not contain any unsaved data:
% EDT0904 TERMINATE EDT? REPLY (Y=YES; N=NO)?
If the user enters Y then EDT is terminated. If N is entered then EDT continues to run. If one of the work files contains unsaved data then [K1] has the same effect as @HALT (see also section “Terminating an EDT session”).
[K2] Interrupting the EDT session
It is possible to interrupt the EDT session and switch to system mode by means of the @SYSTEM statement or by pressing [K2].
The /RESUME-PROGRAM command can be used to return to F mode. After this, the entire screen is output again.
If the work window in which the EDT session was interrupted is not output or is output incompletely after /RESUME-PROGRAM then the original content can be restored with [K3].
If, during the period of interruption, another program is loaded (e.g. with /START-PROGRAM or /LOAD-PROGRAM) or if a procedure is started which loads another program then EDT is unloaded without any query being issued.
[K3] Restoring the screen content, rejecting user input
If the screen content is moved (for example, due to a broadcast message), then [K3] can be used to restore the original state. The screen content (together with any messages output by EDT) is restored exactly as it was before the user entered the first character. The [K3] key can therefore also be used to reject all user inputs and restart entry, for example if the user has accidentally overwritten screen lines which should have remained unchanged with new text.
[K4] to [K15] are treated in the same way as [K3] (see above).