BOOT CAMP 243 (17/09/02)

Protecting your PC, part 1

Everyone knows about the dangers posed by the viruses and worms flying around the Internet and we all keep our anti-virus software updated and take care when opening email attachments (…don’t we?) but there are plenty of other threats to your PC’s well being that you may not be aware of. This week we’ll deal with the attack of the killer volts, next week, the human menace…

In the UK we take the reliability of mains electricity pretty much for granted – in urban areas at least -- but it’s not unknown for high voltage ‘spikes’ or surges to find their way into the supply. These can come from a variety of sources including nearby electrical equipment, grid switching operations and even lightning strikes. In most cases these transients are too small to worry about or are filtered out by the PC’s internal power supply but occasionally one comes along that’s too large for it to handle and if unchecked there’s a very good chance it will fry the delicate microchips inside your machine.

Surge protection extension sockets are a cheap and readily available first line of defence. They can be bought from electrical stockists and PC dealers and a basic 6-way adaptor will typically set you back less than £25. More advanced models with extra facilities, such as surge protection for telephone lines and (usually) pointless winking light cost only a little more.

A much more serious problem is an interruption, however brief, in the mains supply. Power cuts are quite rare these days, nevertheless, they can and do happen, and if one occurs whilst your PC is writing information to the hard disc drive at the very least the data or whatever you are working on will be lost, at worst critical Windows system files could be irretrievably corrupted and the PC may become unusable.

The solution is to install an uninterruptible power supply or UPS. This small box of tricks connects between the mains outlet and the PC. Inside there’s a rechargeable battery and a device called an inverter that converts the low DC voltage from the battery into 230 volts AC. If the main supply fails the electronic circuitry in a ‘standby’ type UPS switches more or less instantly to the battery backup supply. It happens so quickly – usually in less than 10 milliseconds -- that the PC’s power won’t miss a beat. More sophisticated ‘online’ models operate continuously, in other words the computer’s supply mains is derived directly from the battery, which is kept constantly charged, so there is no interruption in the supply if there’s a power cut.

How long a UPS can supply the PC depends on the battery capacity and the power consumption of the equipment it’s connected to. It varies from a few minutes to several hours, but in almost all cases an alarm will sound, or a warning message appears on the monitor screen, so you can save your work and safely shut down. More advanced types come with software that will do this for you automatically, which is useful if your PC is constantly on and liable to be left unattended for any length of time.

A basic UPS for a single stand-alone PC and monitor, capable of powering it for several minutes are usually no larger than a small shoe box and prices start at around £60. As an added bonus most UPS also provide an extra degree of protection against transients and spikes in the mains supply and some makes include insurance cover worth several thousands of pounds for the data and equipment they’re protecting.

It is important to select the correct type for your system; automatic shutdown is definitely worth having and if your PC has to be left on all the time a ‘hot swappable’ battery means it doesn’t have to be switched off for routine maintenance. The batteries -- usually sealed lead-acid types – have a life expectancy of between three to five years. UPS are rated in volt-amperes or ‘VA’. A 300 to 350VA model should be enough for most home setups comprising a single PC and monitor and the usual peripherals, giving at least 5 minutes worth of emergency power.

Incidentally, there’s usually no need to buy a UPS for most laptops. When the battery pack is attached this acts as a UPS when the machine is running from the mains adaptor/charger.

Spring can be dangerous times for PCs. Thunderstorms are more common at that time of year and lightning strikes account for a fair number of modem fatalities, occasionally the PCs to which they are connected are also zapped. The telephone network is well protected but if you subscribe to the boots and braces approach it’s worth investing in an in-line lightning arrestor, or getting a mains surge protection extension socket with the facility built in. The arrestor connects between the phone socket and the modem cable. It can certainly reduce the danger and improve your modem’s chances of survival but if lightning strikes the telephone pole outside your house there’s little that can be done and the best strategy is to always unplug your modem from the wall socket when a storm is nearby or overhead.

Next week – Protecting your PC, part 2

JARGON FILTER

HOT SWAPPABLE

A device or component that can be safely removed and replaced whilst the equipment it is connected to continues to operate

SPIKES, SURGES & TRANSIENTS

Brief increases in mains voltage, varying from a few volts to several thousand volts,

WORM

A type of virus, usually hidden inside another program, designed to penetrate a computers operating system. Once activated it is programmed to replicate and attach itself to other programs or emails

TOP TIP

Suppose you want to send an email in a hurry, it’s so urgent you can’t even wait for Outlook Express to load, or you are using a friend or colleague’s PC. Here’s a way to bypass OE and open an email message window in no time flat! All you have to do is right click on any desktop icon. On the drop-down menu that appears click Send To, then Mail Recipient and hey-presto; a blank email message window pops up onto your screen. Simply delete whatever is in the Subject and Attachment boxes and compose your message as normal.