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1992-01-22
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85 lines
NOTES ON DARKSCRN.COM
Matt Roberts
3 Cedar St., # 8
Montpelier, Vt 05602-3006
07-12-91
───────────────────────────────────────────────────────────────────────────────
DARKSCRN.COM is a simple screen blanker. It's used from the DOS prompt. The
screen goes blank, the cursor disappearing as well. The screen comes back
when you touch a key, but the data that was on your screen has been removed,
and you have just a DOS prompt in the upper left corner. That's about all
there is to it. Told you it was simple.
I wrote DARKSCRN because I didn't need something that automatically blanked
every three, five, or ten minutes. When I'm in a program, I'm usually in it
to do a job and get out. As a result, most of the idle time is spent at the
DOS prompt. Most of the programs I use regularly have a DOS shell, so if I
really need to leave in the middle of a job, I can shell, invoke DARKSCRN,
touch a key when I'm ready to continue, and type EXIT to return to my program.
I have yet to encounter a situation where I wished I hadn't cleared the screen
contents, so I've never bothered to save them. In short, I have simple needs,
so I wrote a simple utility.
A NOTE ON THE WHY OF SCREEN BLANKERS
The inside of your monitor's cathode-ray tube is coated with phosphorous
(unless it's an LCD display). When the electrons hit the phosphorous, it
glows. This is called "exciting" the phosphorous, and creates text, graphics,
and what-not on your screen.
As with people, phosphorous can take just so much excitement. Every time it's
"excited", some of it is used up, and eventually the screen wears out. This
takes a long time, and you shouldn't be alarmed if you haven't used a screen
blanker for years. After all, you haven't used a screen blanker for years (is
there an echo in here?), and everything is probably still fine. The problem
is that the phosphorous wears out in some places more than others, for
instance at the upper left corner of your screen.
The aforementioned corner is where the DOS prompt is parked at the exit of
most programs, such as word processors, spreadsheets, and the like, after
you've been sent back to the system. Since the phosphorous in that corner
(for example only; you may have other trouble spots) is "excited" more than in
other areas, it gets worn out faster. You then get a "hole" in your screen.
Data and graphics can't write to it, because the electrochemical process can't
take place any more. This drives most folks to distraction, and they end up
junking what should have been a perfectly good monitor because of that little
"burn". While hardware prices have been going down, considerably, monitors
don't come free. You can probably extend your monitor's practical life by a
considerable amount by using a screen blanker, thereby saving precious
resources; namely, money.
A FINAL NOTE, AND THEN I'LL SHUT UP (FOR A WHILE)
I have a bad habit of using all eight letters allowed by DOS for my programs.
I don't know why that is, but I don't feel quite right unless I've got an
eight-letter filename. I finally stopped adding extensions to my directories,
2
but only because I couldn't read my DIR output any more.
Anyway, you can rename this file to anything your little heart desires; D.COM,
DS.COM, WHOCARES.COM, etc. This will save a little typing if you use the
blanker a lot during the day. I've programmed my Alt-F1 key combo to call the
blanker, so I left the long name, but you do what's right for you. If you do
change the name, however, and then pass the blanker along to someone, I'd
appreciate it if you'd rename this document file so it matches the blanker's
new name. That'll make it easier for folks to find the documentation, and to
get in touch with me if they have trouble with any of my programs.
DARKSCRN.COM was created using ASIC 1.00, a shareware BASIC compiler by David
Visti. Registration is currently only $10.00 for version 3.01, which is a
major bargain in my opinion. He can be reached at P.O. Box 2952, Raleigh, NC
27602-2952. I compiled this with version 1.00 because it creates a slightly
smaller .COM file. It's possible that it loads just a tiny bit slower, but I
didn't think it was enough to warrant the extra 20 bytes or so.
All right, I promised I'd shut up, so I will. Comments, suggestions, and
criticisms can be sent my way, via the address above, and are greatly
appreciated. I want to write quality software, and I need your help to do it.
Thanks.