BIOC Ctrl-W & Ctrl-X Updates
by Stuart Baker
This article describes an update I developed for the BIOC driver. Yes, once again I am making changes to BIOC. I guess it is difficult to totally ignore a past love. The world of computers has undergone a lot of change since I initially developed BIOC. Users of PC word processing software have probably noticed that virtually every program performs the backspace word function in the same manner. Once you are accustomed to this uniformity, using BIOC's backspace word (Ctrl-W) is rather disconcerting. In an attempt to close the gap, I present the following changes.
Before starting this discussion the term "word delimiter" needs to be defined. BIOC defines a word as one or more consecutive upper or lower case letters or numbers. All other characters are considered word delimiters. If you do not like the default definition of a word delimiter, you can change it by modifying the bit table defined by the label BKWD.TBL. Now that we have defined word delimiter, lets proceed.
The original BIOC backspace word functions as follows:
The new BIOC backspace word functions as follows:
By skipping all leading word delimiters, the Ctrl-W function now traverses a line containing a lot of white space using many less key strokes. By stopping on the first character of a word, you are logically located at the column you wish to change. All and all this is a big improvement over my initial implementation of backspace word. There is also less trauma when I switch between OS/32 and my PC word processing software.
Since the position of the cursor at the completion of the function is different than the original Ctrl-W command, users accustomed to the original command will have to adjust their thinking. After using the new code for only a short time, I preferred it to the original BIOC. I need less keystrokes and can perform editing much faster.
One function I used Ctrl-W for was locating imbedded control characters. If Ctrl-W ever stopped in the middle of a word, all I had to do was type Ctrl-_ to delete the control character. Now I have to remember that I am actually positioned one character to the right of the control character and I need to enter Ctrl-B Ctrl-_ to delete the character. Considering the number of times I have actually used Ctrl-W to locate and delete control characters this is a small inconvenience.
Once one starts making changes, it is hard to stop. The next BIOC change was to the cancel line (Ctrl-X) command. The original Ctrl-X command puts out a carriage return line feed to allow you to start data entry on a clean line. All of the data you previously entered remains on your display. Since the Ctrl-X command is destructive, the fact that the canceled data remains on your display is disconcerting. It should disappear, as it does when you erase a line using Ctrl-H, hence the new Ctrl-X command.
The new Ctrl-X starts at the current position in the line and moves to the left until the beginning of the line is reached. It then starts writing out spaces until the end of your entered data is reached. Then the cursor moves to the beginning of the line with a series of backspaces. If you are running on a high speed terminal, the data appears to vanish from your screen, just as if you had never typed it in the first place. This is consistent with the cancel function, since the data can not be recovered with the Ctrl-F or Ctrl-Z commands. If the BIOC line you are using has the hardcopy backspace protocol selected, the Ctrl-X function just puts out the carriage return line feed sequence.
If you are using a slow speed line, such as a 1200 bps modem, the cancel request will take a noticeable but not objectionable length of time. If, for example, you were at the end of a 40 character line, it would take about one second to erase the characters from your screen. At slow speeds it is actually entertaining to see all of the work that must be performed to erase the line.
I have placed the BIOC update file for the R08-03 version of OS/32 in the public directory on the interc bbs. The file name is BIOC83.UPD. For those of you using PCs or PASSPORT, you can call in and pick up the file. The file has also been submitted to Ron Stordahl for placement into the Interchange library. If any users want a BIOC update file for the R08-02 version of OS/32 please contact me, I can be persuaded to generate a file for that version of OS/32 if there is interest.
Well that about does it for this issue. I have just installed the R08-03.1 update to OS/32 and hope to find time to look at the CTD driver again. Stay tuned for more on CTD in the next news letter (maybe). I hope to have some hands on experience to report. Looking forward to seeing everyone at Interchange 90.
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