Scor­pio News


January–March 1988, Volume 2, Issue 1

Page 24 of 39

that itself asked ‘W/w’, and which on exit asked: “BACKUP DONE – PROCEED (with original command)?".

I have now completely changed the system of command access. The philosophy now is that any command that can cause a disk operation, cursor movement, printer output or change the printer or screen format is protected in some way.

All lower case (a-z) commands, except “f”, are converted to upper case, allowing great shortening of the dispatch table code. Protection is applied to ALL A-Z commands EXCEPT 1,J,M,D,F,f,V. (M,D,F,f require parameters anyway, so they can be aborted, and I,J and V commands do not cause serious problems if invoked in error.)

The remaining A —Z commands can have unwanted results if accessed in error, so they are ALL accessed via a lead-in key. I have chosen ‘- Q’ for this purpose, since it was not used as a command, and ‘Q’ is near the control key. A small amount of extra code has been added which has widened the scope of this, so that a total of four key sequences are available to access the required protected commands. e.g.;

“QE or “Qe or *Q*E or *Q“%e keys will ALL access the ‘E’ command.

Where the command in question can have particularly awkward results, such as ‘E’, ‘W’, ‘K’ etc.;, a further prompt is printed for security. Since most of these extra security keys are only used a few times in a session, this double protection is not a problem.

In some cases like formatting, the “Q protected command requests extra parameters, and so this request provides a way of escape, without the need for GEMPEN to ask if it is safe to proceed.

Modifications to Commands.

a) F/f – Find and Replace

  1. ^X during string input will abort command without cursor moving. Originally once a string was started there was no way to abort, and – Z. would cause the cursor to move to some other place which depended on what had been entered.
  2. Find and Replacement Strings now allow ? wildcard Characters. (Advisable not to use ?’s in replacement string since they will be left in the text.)

This is an OCR’d version of the scanned page and likely contains recognition errors.

Page 24 of 39