They avoid phosphor burn. It's not enough simply to have the
screen simply black out, because people will think the machine has
been turned off and they'll press the power button to turn it back on.
They protect sensitive information left on the screen
They're important in a business environment, where you want a standard
corporate image to be presented on every unattended computer so as to look
They're useful for advertising
They can usefully occupy a computer's idle time
Why The World Needs More Savers
For the business and advertising sections mentioned above, each company
needs its own saver.
The idle time of Windows machines has not yet been fully used.
Seti@Home is one project
that uses screen savers to decode astronomical data and search for
Internet savers are still in their infancy. No one has written a really
useful or fun screen saver that traverses the web, or where you give it a
long-term list of slow downloads and it does them during idle-time.
Screen savers are by definition graphical animations. The technology in
this area is fast advancing. If we stopped producing savers, they'd all get
Savers Are The Most Treasured Programs On A System
Savers are insidious. You leave your computer for five minutes, and you
come back, and someone's program has loaded itself onto your machine. So a
saver is a program that is welcome to load itself and sneak itself into the
user's attention (and the user doesn't mind). Good for advertising
Moreover, savers bypass the guilt that might be associated with loading
some program. Consider the game Solitaire. If the user has to
open a folder and click on the game, they have committed a conscious act of
voilition. During office hours this induces guilt. But if the saver comes
up automatically then the user ends up playing but without the guilt
associated with launching the program.
If you have installed Plus! or my ScrHots utility, then the saver is only
a mouse-move away: moving the mouse into a corner of the screen causes it
to start up immediately. This means that the screen saver is the
single most immediate
program on the user's entire machine. Even to start Word
they have to click on the Start menu and click on the Word icon.
(But only one saver can be selected at a time. You therefore have to
fight to make your saver better than anyone else's).
The immediacy of their launch makes them excellent for the user to while
away a few odd moments, perhaps when waiting for a file to download or
making a telephone call. They're much better than Windows Solitaire for
this purpose. I like playing with my interactive 'Massage Puzzle' saver,
also available at the above web site.
Also, if you desktop is all cluttered, or if you are using Word
full-screen, then a screen saver is the only temporary program that you can
launch without closing your session or rearranging windows.
Savers Make A Good Programming Exercise
Graphics are a good teaching exercise. The fact of a concrete
visualisation makes it easier to follow your program. It's for essentially
this reason that LOGO used to be the most popular teaching language in
schools (at least in the U.K.)
Graphical demos are a way of showing off a team's technical prowess.
They used to be all DOS-based. Nowdays they are moving over to Windows.
There are a lot of graphical demos out there waiting to be written.
Turning a graphical demo into a saver gives it a little more life. (If
you simply left it as a .exe after writing it, then you'd never run it
Essentially, the above two points are saying that screen savers are the
only way that third parties will be interested in downloading graphical
demos. If you want to write a graphical demo then you should make it as a
screen saver to ensure a wider audience.
Screen savers are expected to run full-screen. This makes them ideal for
full-screen OpenGL or DirectDraw or Direct3D. When you write a full-screen
standalone executable then it's kind of irritating for the user when it
takes over the entire screen; but if it's a saver, then it's okay.
If you use a library like my ScrPlus,
then when writing a screen saver you
can get straight down to the interesting graphical animation programming
straight away. If you were instead making a stand-alone executable you'd
have to spend lots of time worrying about windows fripperies and
user-interface things, and no one likes doing that.