SDF saves syntactically correct commands or statements locally for each task. The INPUT-HISTORY operand in the MODIFY-SDF-OPTIONS command activates/ deactivates or resets the input buffer. It also defines the maximum number of inputs that can be saved. Each time this maximum is reached, the oldest input is deleted. The saved inputs are automatically numbered (input serial number).
Inputs in guided dialog are saved in ACCEPTED form, while those in unguided dialog are saved in INPUT form. The commands or standard statements SHOW-INPUT-HISTORY and RESTORE-SDF-INPUT are not saved. ISP commands are only saved if PASSWORD-PROTECTION has been set to *NO or *SDF-ONLY.
The command (or standard statement) SHOW-INPUT-HISTORY shows which inputs are stored.
The RESTORE-SDF-INPUT command redisplays a specified stored input on the screen. The user can then use the displayed command or statement again as input, either as it is or with modifications. This saves having to type the whole command or statement again.
INPUT-HISTORY=*OFF deactivates the input buffer. Stored inputs are retained.
If INPUT-HISTORY=*ON is entered, inputs are saved again.
INPUT-HISTORY=*RESET resets the input buffer, i.e. saved inputs are deleted and subsequent inputs are stored.
Protecting “secret” operands
Values specified for “secret” operands which match neither the default value nor a value defined via SECRET=*NO are stored in the input buffer with “^”.
In unguided dialog when these values are displayed again via RESTORE-SDF-INPUT, the user can do one of the following:
send off the command/statement unchanged. In this case, SDF displays a blanked input field for each secret operand where the user can enter the desired value.
delete the “^” and insert the desired value directly before sending off the command/statement.
Values specified for operands which are not “secret” are stored in the input buffer in plaintext. In individual cases these inputs can contain information that the user considers sensitive (e.g. procedure parameters). The following steps will prevent such inputs from being displayed again via SHOW-INPUT-HISTORY or RESTORE-SDF-INPUT:
Before entering sensitive input, the input buffer must be deactivated and then activated again. If the inputs have already been saved, the input buffer can be reset with *RESET, but it must be remembered that this will delete all saved inputs.
Removing protection of “secret” operands
The protection of “secret” operands can only be removed in interactive mode by entering INPUT-HISTORY=*ON(PASSWORD-PROTECTION=*NO). Thereafter, values specified for “secret” operands are stored in the input buffer in plaintext. ISP commands are then also stored in the input buffer.
Under this setting, passwords are displayed on the screen in plaintext with the SHOW-INPUT-HISTORY or RESTORE-SDF-INPUT command, which means that they are visible to unauthorized users. You should therefore ensure that whenever you leave your terminal no unauthorized users can output the contents of the input buffer. If your terminal does not possess any appropriate security mechanisms (e.g. chipcard terminal), you should at least delete the input buffer before you leave.