Hardware > Buying & Owning Hardware

Buying a PC: Understanding the Technicalities

By Lasa Information Systems Team

Overwhelmingly, the standard machine for office work is a Windows-based personal computer (PC). There are alternatives: the Apple Mac has its adherents - particularly in the design world - and the Linux operating system has growing support. This article provides a plain language explanation of terms used in computer specifications.

The Windows PC currently has the widest range of available software and most specialist voluntary sector software is written for Windows. Voluntary sector staff are very likely to be familiar with the PC, and training, support and other services are widely available. As a result most organisations will need a very good reason to use something else.

Remember the golden rule: decide what you want to do; choose software which will do that; select hardware which will run the software. Most voluntary organisations will be best advised to put their energies into deciding what to do, rather than getting involved with unusual hardware. Better to be innovative in the use of IT to deliver better services rather than a guinea pig for innovative IT.

Specifications

One of the problems in advising on buying a PC is that specifications and prices change so rapidly. We provide sample specifications and costs, updated every few months — see the knowledgebase article Buying a computer.

Interpreting the Specification

You might see a machine with the following specification - this is NOT a recommended specification, just an example for illustration purposes. For each part, we explain what the technical details mean.

• Intel Pentium 4 Processor 2.5 GHz - see Processor
• 256 MB DDR RAM - see Memory
• 40 GB Hard drive - see Disk Drive
• 17" SVGA Colour monitor - see Monitor
• nVidia TNT2 M64 32MB Graphics card - see Video Card
• 48x CD ROM - see CDs and DVD
• Creative Sound Blaster 128 PCI sound card - see Sound and Speakers
• 56K modem - see Modem
• Two USB ports - see Ports
• Microsoft mouse & keyboard- see Mouse and Keyboard
• Tower case - see Case
• 10/100 Ethernet network card - see Network Card
• MS Windows XP Pro- see Operating System
• MS Works 6.0 and games bundle - see Bundled Software

Processor

At the heart of any PC is the central processing unit, or processor. The history of the PC has been dominated by processors from Intel, although in recent years other companies like AMD have provided very viable alternatives.

Intel has the sales advantage of providing 'the real thing', but there is no evidence that computers powered by rival processors are in anyway inferior.

Clock Speed

Processors are rated according to their 'clock speed' measured in MHz (millions of cycles per second), and GHz (thousand million cycles per second). Clock speed gives a measure of the speed of the computer, but a computer with a 2000 MHz (or 2 GHz) processor will not be twice as fast as one with a 1000 MHz (or 1 GHz) processor. Other factors, like the speed of hard drive (both in terms of the quoted rpm and access time given in milliseconds) and the amount of memory will also determine the speed of the machine.

Memory (RAM)

Many people are confused by the difference between computer memory (RAM, standing for Random Access Memory) and disk storage. Memory is what the computer uses to hold and manipulate information while it is working, and takes the form of memory chips. Anything in memory is lost when you switch the machine off. Long-term storage is provided by the hard drive, floppy disk, Zip disk, tape, CD or DVD.

The amount of memory in a machine, measured in MB (megabytes), is very important in determining performance. Increasing the amount of memory in the computer can be the cheapest way of speeding it up. The amount of memory needed is determined by the size of your software applications and the number that you have open at the same time.

Disk Drive

Hard (or disk) drives are used for the long term storage of information. Disk space can only be upgraded by replacing the existing drive or adding new drives and so you should ensure you buy a PC with sufficient disk space for your foreseeable needs. Larger disks cost little more than smaller alternatives so it makes sense to buy something with plenty of capacity for the future.

Monitor

Your computer's screen, or monitor, is one of the most important components you will buy. You'll spend many hours looking at it and a poor screen will cause stress and eye strain. Many computers at the budget end of the market are sold with cheap monitors. It is well worth spending a bit more for a better quality monitor, from a big-name supplier like Sony, Philips or IIyama.

Monitor size is very much a personal choice, although the trend is towards bigger models which can display more information on screen. The size of the monitor is measured diagonally across the screen (although subtract 1.5 inches to get to the viewable area). A 15 inch monitor is the minimum practical size with 17 inch and larger, becoming more widely used as prices fall.

Flat screens, based on the same technology as portable screens, are available and save a lot of desk space. Although they are more expensive than conventional monitors they are becoming much more affordable as prices continue to fall.  Since flat screens use much less electricity than traditional Cathode Ray Tube screens, over their lifetime they will cost you less.

Avoid really bargain flat screens as the image quality will undoubtedly be poor.

Video Card (graphics card)

The video card provides the electronics that run your display screen on your computer's monitor. Most office applications are fairly undemanding in terms of video output, in contrast to home computers used to play games, and so most office computers don't require the most sophisticated video cards.

CDs and DVD

Most software is now supplied on CD, making a CD-ROM drive a standard component. A standard CD can store 650 MB of information.

CD-ROM drives are advertised according to their speed - expressed as a multiple of the speed of the earliest drives, for example 48x or 52x.

CD rewrite drives can write to CDs.

CD-R is a 'write once' technology: you can copy information on the CD but there's no way of erasing or overwriting the data. Once it's written it's written.

CD-RW overcomes this limitation and allows disks to be erased and new data written. The extra flexibility of CD-RW makes it the more attractive technology - it provides a useful option for backup and archiving.

However older CD-ROM drives may struggle to read CD-RW disks and so if you are using a CD writer to distribute data or software its important to use CD-R disks.

DVDs (Digital Versatile Disk) look like CDs, but store over seven times as much information - 4.7GB, enough for a feature film, which provides the major application for DVD. DVD drives will also read CDs.

At the time of writing there are few office applications that use DVD. DVD rewrite drives are also available. However if you are creating and editing video and want to make your own movies for distribution then DVD is the way to go. Investing in a DVD RW drive can also be an affordable and convenient back up solution for smaller organisations that need a higher storage capacity than CDs provide.

Sound and Speakers

While it might appear harder to make the case for a sound card in an office computer, sound is now a standard component and worthwhile especially if you need to use multimedia applications, voice recognition systems and for Internet use. Sound Blaster has set the standard for sound, and a genuine Sound Blaster card will minimise compatibility problems.

Modem & Network Card

A modem is necessary if you need to connect to the Internet by dialling up the service provider over a normal phone line. Some PCs come with internal modems or can buy an external modem to connect traditionally to the USB port, (see Ports). As prices fall and fast broadband (ADSL - Asymmetric Digital Subscriber Line) access becomes affordable, many small offices are now connecting via their networks so a network card is more important to have than a modem. Standalone PCs can connect to broadband with USB ADSL modems .

Ports

Computers come with a variety of ports for connecting peripheral devices.

Parallel and serial ports have been used virtually since the PC was invented and are still included for connecting printers etc.

PS/2 ports are generally included for connecting keyboard and mouse.

USB (Universal Serial Bus) provides a single standard socket at the back of the PC to connect peripherals like printers, PDAs (Personal Digital Assistant or handheld computers), external CD writers, modems, digital cameras and scanners etc. Hubs can be purchased to allow a single USB port to connect to a number of devices.

USB2 is much faster than ordinary USB but the peripheral device being connected to the port has to be designed for USB2 to take advantage of the increased speed.

IEEE 1394, (an Institute of Electrical and Electronics Engineers standard) otherwise known as "firewire", ports are generally used for digital video (DV) cameras to allow for fast data transfer and also for some external CD writers.

Mouse and Keyboard

Many budget machines are supplied with very cheap mouse and keyboard which will be more tiring to use than a better quality ones or will just fall apart! Consider paying more for good quality data input equipment in order to avoid fatigue and possible repetitive strain injury. There are also variations such as cordless mice and keyboards and infra red mice which do not have a ball and are easier to keep clean.

Case

PCs are available in a tower case which sits beside your desk or desktop case which fits under the monitor. Tower cases generally have more room for additional components like hard disks and modems.

Network Card

Network cards are fitted inside the PC to enable it to be connected to a network. They vary widely in price, but many network engineers take the view that reliability is such an important factor that they recommend more expensive cards from a reputable manufacturers. Ensure that the network card you buy is compatible with your network cabling. Network cards for wireless networking are also widely available.

Operating System

The operating system is the software that your computer runs when it's first switched on. It enables you to manage files and folders, install and remove software, and access the software you've installed. Most people use Microsoft Windows for their operating system, nowadays usually Windows  2000 or XP.

Because of the similarity in names (and numbers) it's easy to get confused between Microsoft Windows 98/2000/XP and Microsoft Office 97/2000/XP. Office isn't an operating system; it's a package of applications for word processing, spreadsheets, presentations, databases, email and so forth.

Windows (the operating system) has to be installed on the computer in order to install and use Office (the application). At the time of writing many voluntary sector agencies are still using Windows 98 as the operating system for PCs. Microsoft support for Windows 98 has now ended so upgrading to a later version of Windows is advisable. Windows 2000 Professional (replacing Windows NT Workstation) provides greater reliability and security. Windows XP has become more commonplace as organisations buy new PCs - make sure you specify the Pro version rather than Home for office machines.

Bundled Software

Some suppliers will offer 'free' software as part of the deal, with some making a big selling point of a wide range of packages. Don't be swayed by this unless the software on offer is what you actually want. There are big advantages in using standard packages like Microsoft Office, so don't make the mistake of adopting some less common system simply because it is given away free.

Registered charities shouldn't normally pay full price for software, but instead should make use of the substantial discounts that are available on products for charities and educational organisations. These discounts are only available from software suppliers which specialise in the educational and voluntary sector.

Charities can get discounted software through National Council for Voluntary Organisations, and other charity software suppliers.