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BOOT CAMP 225 (14/05/02)
SCREENSAVERS
One of the more bizarre aspects of our relationship with the
PC is the seemingly endless fascination with screensavers. What started out as a
simple utility to overcome a problem known as ‘screen burn’ has evolved into a
minor counterculture encompassing many diverse fields, including advertising and
promotion, security, multimedia entertainment and even the search for
extraterrestrial intelligence or SETI, but more on that in a moment, after a
brief history lesson.
Screensavers predate the desktop PC by several decades, back
to the earliest days of cathode ray tube (CRT) visual displays when it was found
that a continuous or static image, such as a radar plot, would eventually be
permanently burned into the phosphor coating on the inside of the screen’s
faceplate. Various solutions were developed, from dimming or blanking the
display when it wasn’t being used, to physically rotating the picture tube,
though clearly this was only practical on tubes with round screens. Screensavers
as we know them today first appeared during the 1960s and were used on the VDU
terminals connected to early mainframe computers, which typically displayed
fixed lines of alphanumeric characters, for hours on end, often causing
permanent screen burn in a matter of months.
First generation computer monitors were almost exclusively
monochrome, moreover they were relatively fragile and very expensive. Switching
them on and off repeatedly shortened their lives so the answer was to keep them
switched on and ‘warmed up’, displaying a simple graphic, when not being used.
The first screensavers were usually nothing more elaborate than a square or
circle that roamed slowly around the screen, to prevent burn in.
The need for screensavers continued into the early days of
the desktop PC, which also used monochrome displays and mostly displayed only
lines of text but by the early 1980s colour monitors had begun to appear and the
rapid shift from text-based displays to graphical interfaces, like Windows had
begun. This plus improvements in CRT design, power management systems and
latterly LCD screens means that strictly speaking screensavers are no longer
necessary…
Whether or not we need screensavers nowadays is largely
irrelevant, as they have taken on a life of their own, but what exactly are
they? Screensavers are basically
executable files – a program in other words – but instead of the usual ‘*.exe’
extension screensaver files almost always have a ‘*.scr’ ending. This means Windows knows what to do with it,
which folder to store it in (usually C:\Windows\System) and to associate it with
the Display Properties utility in Control Panel, from where most screensavers
are usually selected and configured, though some screensavers have their own
custom setup screens.
Screensavers work in a variety of ways, the simplest is to
blank out the screen after a predetermined period but more usually they are used
to display static or animated images – pictures, videos, graphics, text etc. --
they can also be programmed to play sounds and even run programs in the
background using a technique called ‘distributed computing’. This is a clever
idea that makes use of large number of PC’s – otherwise sitting idle running
screensavers -- to solve vast computational problems. The most famous of these
is the Seti@home project, which uses desktop PCs
to sift through millions of hour’s worth of radio signals from space, looking
for evidence of extraterrestrial life. There’s more information from: http://setiathome.ssl.berkeley.edu/,
and details of other distributed computing projects at: http://www.aspenleaf.com/distributed/
The vast majority of screensavers, however, are merely
decorative or carry promotional messages and serve no practical purpose, though
there are a few exceptions. Screensavers can be quite useful as sources of
real-time information, from a simple time and date display to stock market
prices. Large corporations tend to be big fans and in many offices a screensaver
of the company logo is obligatory and helps to project a unified image by
discouraging personalisation amongst the staff. Screensavers can also be quite
effective for securing your PC against unauthorised tampering, whilst you are
away from your desk. One of the options in the screensaver control window is
Password Protection. It’s not going to stop a determined intruder but it’s
enough to deter most casual snoopers.
Commercial screensavers used to be big business and
collections like After Dark – the home of the famous Flying Toasters – were an
essential addition to any early Windows PC. Nowadays a screensaver has to be
very special indeed to persuade PC users to pay for it, rare examples include
the ‘Dancing Baby’ and ‘Aquarium’; the Internet is awash with hundreds of
thousands, quite possibly millions of free downloadable screensavers, though
most of them are blatant advertising. To get a taste of what’s available simply
type ‘screensaver’ plus an interest, celebrity or product into the search field
of a search engine like Google (ww.google.com).
Creating your own screensaver is another option and you don’t
need any additional software if you’re using Windows 98 onwards. The simplest
DIY screensaver is 3D Text, which has been included with Windows since the OSR2
release of Windows 95. Just select it from the list in Display Properties
(Screensaver tab) and click the Settings button; the dialogue box that appears
allows you to enter your own text, select the font, texture and control the
motion of the graphics. Windows XP has several custom screensaver options,
including the facility to display a slide show of the pictures stored on your
machine. Users of earlier versions of Windows needn’t miss out on the fun,
freeware and shareware slideshow screensaver programs can be downloaded from the
following web sites: http://www.freewaresite.com/
screensavers/slideshow.html
and http://www.mindbeat.com/
However, if you’re really serious about creating your own
screensavers you will need something a bit a more sophisticated but once again
there’s plenty of freeware and shareware programs on offer, for a wide selection
just type ‘screensaver utilities’ in the search field at www.tucows.com.
Next week – Recovering lost images
JARGON FILTER
LCD
Liquid crystal display, flat screen display technology used
on laptops and becoming increasingly popular for desktop PCs
MAINFRAME
Large and powerful computer, the earliest machines often
occupied several air-conditioned rooms and had to be tended by teams of
technicians
VDU
Visual display unit – old name for a computer monitor
TOP TIP
It’s amazing how many people spend their time staring blankly
at screensavers so if you’re looking for something a bit more visually
interesting try a freeware program called Drempels. The author claims the swirly
coloured patterns are hallucinogenic! If nothing else it might make those
interminable lunchtimes go a bit quicker. Instructions and downloads at: http://www.geisswerks.com/drempels/.
They can’t touch you for it but watch it at your own risk, and don’t blame us if
it turns your brain into chicken soup…
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