EXPLANATION OF COMPUTER TERMS
1. INTERNAL COMPONENTS: Located inside the PC case and connected to the "motherboard".
Power Source Unit (PSU)
Converts the 220V AC mains current into the DC 12V and lower voltage current needed by the PC components. A decade ago a PSU would typically deliver 200W. Hi-end desktop computers nowadays often require 600W or even 1,000W.
Motherboard ("mobo")
Board with electronic circuitry to which all the other PC components are plugged or connected, serving as centralised control and as a hub for the flow of information.
Processor (CPU-Central Processing Unit)
Central chip for information, mathematical, logical and memory processes. Its speed may affect the response of the whole PC. Present day multiple-core CPUs can deliver impressive speed, especially for applications or games especially designed for parallel processing.
Graphics Card
Converts information from the CPU into the display you see on your monitor's screen. Also performs special visual functions, such as reflections in computer games. If the graphics card is inadequate, the display will lack continuity, showing stutters.
Memory (RAM)
Temporary storage for computer programs and data. Needs to be large enough to store the Operating System and the main programs being run. Otherwise some of them will use the hard disk as memory, which considerably slows down the PC. The ideal RAM size (in terms of both cost and computer speed achieved) depends on the Operating System and the type of programs that will run in the PC.
Hard Disk drive (HDD)
Permanent storage for computer programs and data. Needs to be large enough to store the Operating System, all your programs (applications and games) and all your personal data files. Since they increase continuously, a PC has to be purchased with a disk large enough to have plenty of free space, thus avoiding the need for later upgrades and software re-installations.
CD/DVD drive
Front-case unit that reads CDs and DVDs. Most units can also record special blank CDs and DVDs.
Fans and coolers
Internal cooling devices, crucial for the reliability and longevity of the internal components. They come in different sizes and types according to whether they are fitted to the case or to particular components such as the Processor, the Graphics card and the "North Bridge" chip in the motherboard.
2. EXTERNAL COMPONENTS: Located outside the PC case and connected via cables or wireless.
Uninterruptable Power Supply (UPS)
Guarantees a) surge protection, b) stable electricity supply and c) battery backup for up to 30 minutes in case of power failure in the premises.
Monitor or Screen
Either the traditional CRT - Cathode Ray Tube - or the modern TFT-type flat device. Any type will work, but the size, "resolution"—number of "pixels" or points it can show horizontally and vertically—and other technical parameters need to be adequate for the programs or games the user will run in the PC.
Printer
Normally prints A4 paper and also smaller sizes and envelopes. Some larger home units can print A3 as well. They belong to different technologies, the most common ones being Inkjet, Black Laser and Colour Laser. The choice of technology is not easy, as printing speed, cost and quality depend on both the printer model and the type of printing task performed.
Speakers
An often overlooked component. Even for low-budget units, its choice is crucial for an adequate reproduction of sound effects and hi-fidelity music..
Modem/Router
Device(s) that connect the PC to the Internet and often also network-connect the different PCs in an office or household.
USB Flash Key
Keyring-type device that allows to backup or move around personal files and even applications. Rewritable CDs and DVDs are nowadays largely replaced by USB keys which have mostly larger capacity and are more convenient as they appear to the PC user simply as additional disk drives .
3. SOFTWARE: Programs installed in the PC, stored in files in the hard disk.
Operating System (OS: "Windows", "Linux" or others)
Centralised computer program that a) controls and syncronises the behaviour of the PC components, b) organises the loading of programs and data from hard disk to memory and viceversa, c) organises how the different programs are processed and d) prepares the display of the "windows" you see on your monitor.
Over the last two decades the most popular OS's have been Microsoft DOS in many versions and then Microsoft Windows in many versions (3.0, 3.1, NT, 95, 98, Me, 2000, XP, Vista and 7). Windows runs at present in 91% of the world's computers, most of them with the XP version.
Graphical User Interface (GUI)
Part of the Operating System that determines the visual display format and organises the information shown on the monitor. It is also said of particular visual interfases of some programs and games, which may have a special design and be largely controlled by the program/game rather than by the Operating System.
Applications and Games
Programs that the user decides to install in the PC. The choice of programs to run, and also of which ones will run at the same time, is important for the effectiveness and reliability of the results.
Utilities
Programs that are run—sometimes permanently other times on demand—in order to perform functions pertinent to the running or maintenance of the PC itself, such as AntiVirus, File Management or Hard Disk maintenance.
Drivers
Every hardware component needs a driver, which is a program or set of files that tells the Operating System information about the component so that the PC can handle the latter properly. Many drivers, such as the ones for Hard Disks, CD/DVD drives and USB Flash Keys, come with the Operating System which installs them automatically as soon as the component is installed/plugged. Other drivers—typically for Graphics Cards—are provided in a special CD which upon insertion automatically performs the necessary installation into the PC.
Network Software
Program that connects computers into a LAN (Local Area Network) or larger office networks. For households and SoHo's, normally no special program is needed as the functionality is provided by the Windows Operating System and the Modem/Router driver.
