Glossary of technical terms

2D

2D stands for two dimensional. This is commonly used to describe the display mode of a video card when it is not in 3D mode. Most programs like word processors, web browsers, and the operating system user interface operate in 2D mode although some with advanced user interfaces may operate in 3D mode. Programs like many games and many visualization programs operate in 3D mode.

3D

3D stands for three dimensional. This is commonly used to describe the display mode of a video card when it is displaying three dimensional objects as in many games, engineering, and three dimensional artwork programs. Most operating systems currently (2006) operate in 2D mode but some newer ones are starting to support 3D user interfaces.

AGP

A kind of expansion slot. AGP stands for accelerated graphics port. It is a faster version of PCI which was designed to speed up video card data transfers. Newer computers use the faster and more flexible PCI-Express x16 slots for video cards.

analog

In the context of computers, analog is a method of representing data with a continuous range of values. An analog voltage varies between minimum and maximum values to represent the datum. For example, a VGA monitor uses an analog voltage to represent the brightness of a color component which makes up an image. Most things inside a computer are digital rather than analog. Analog values are not commonly used. Analog is used for controlling things like the image on a CRT monitor or a sound being generated through speakers. But even in those cases, most of the computer's handling of those signals is done digitally and is converted to analog just before driving the monitor or speaker. When analog data is sent through a cable, the accuracy of the data is degraded to some extent. The data degrades even when sent through high-quality shielded cables. This is as opposed to digital transmission where the data (barring serious problems) received is identical to the data transmitted.

BIOS

BIOS is short for Basic Input Output System. Your BIOS is a program which controls the basic functionality of various pieces of hardware in your computer. Motherboard BIOSes let you change things like the speed of your RAM, the speed of your AGP port, how your expansion slots work, etc. You can find basic information about motherboard BIOSes here. Video cards also have BIOSes.

bit

Bit is short for binary digit. It is the smallest unit of storage in a computer. It has two possible values: 0, and 1. Computers use bits to keep track of things. Since a bit can only store two values you have to group a bunch of bits together to store larger numbers of values. For example, a byte is made up of eight bits and can store all the integers between 0 and 255. Computers have a lot of storage these days so you're more likely to run into things like megabytes and gigabytes.

boot

Boot is short for bootstrap.

bootstrap

Bootstrapping refers to the process of loading and starting an operating system. It's derived from the phrase "pulling yourself up by your bootstraps". It is often called "boot" for short. A cold boot is a bootstrap which happens immediately after the computer has been turned on. A warm boot is one which happens when the operating system restarts without turning the computer off.

byte

A byte is made up of eight bits. A byte is large enough to contain all integers between 0 and 255. Bytes are the standard unit of storage used in computers. Modern computers tend to have lots of bytes of RAM, hard disk space, etc. so amounts of storage tend to be given in megabytes or gigabytes.

cache

A cache is a small amount of high-speed memory which keeps a copy of data which is stored in lower-speed memory. A cache holds copies of the most commonly accessed data. When the data needs to be accessed, it uses the speedy cache if possible and only uses the slower memory if the data is not in the cache. As a result, accessing cached data is sped up substantially. A CPU has a cache which has copies of some of the data kept in the motherboard RAM. Most CPUs actually have at least two caches: the primary cache (L1 cache or level 1 cache) is the fastest and the secondary cache (L2 cache or level 2 cache) is slower and usually much larger. When the CPU accesses data, it accesses the data in the primary cache if possible. If it's not in the primary cache then it tries the secondary cache. If it's not in either of the caches then it must access the much slower motherboard RAM.

CPU

CPU stands for central processing unit. This is the main silicon chip on the motherboard which does the general purpose processing for the computer. Most CPUs in PCs are made by Intel or AMD.

CRT

CRT stands for cathode ray tube. CRT computer monitors are the older style ones which use TV-type tubes to display images. CRTs are large, heavy, and consume a lot of power compared to LCD monitors. CRT monitors can display reasonably sharp images at many screen resolutions. LCD monitors are perfectly sharp only at their native resolution (or their native resolutions divided by 2, 3, etc.) and display other resolutions relatively poorly.

DDR

DDR is short for double data rate. Synchronous memory chips operate at a given clock rate. Single data rate memory can access one value per clock. So a 100 MHz single data rate memory chip has a peak data access rate of 100 million accesses per second. DDR memory can access two values per clock. So a 100 MHz DDR memory chip has a peak data access rate of 200 million accesses per second. Other common forms of DDR memory are DDR-II and GDDR3. They have different technical specifications than plain DDR but they also access two values per clock.

device driver

A device driver is a software which allows access to a piece of hardware. For example, you must install a printer's device driver for the operating system to be able to use the printer.

digital

In the context of computers, digital is a method of representing data with a discrete range of values. This is as opposed to analog which represents data with a continuous range of values. Most things inside a computer are digital rather than analog. Analog values are not commonly used. Analog is used for controlling things like the image on a CRT monitor or a sound being generated through speakers. But even in those cases, most of the computer's handling of those signals is done digitally and is converted to analog just before driving the monitor or speaker. Data transmitted through a cable digitally (barring serious problems) loses no accuracy. The received data is identical to the transmitted data. Analog transmission, on the other hand, suffers some degradation when going through the cable.

display adapter

A display adapter is hardware which displays images on your monitor. The term "display adapter" can refer to both video cards and integrated graphics.

display driver

A display driver is software which allows other programs to access and use a display adapter. You must have a display driver installed in order for your display adapter to do anything other than the most basic operations. Most operating systems have a default display driver which will work for most display adapters but has limited functionality. In order to use the more advanced features like three dimensional graphics, a full display driver designed for that specific display adapter must be installed.

driver

Driver is short for device driver.

DVI

DVI is a digital video standard introduced in 1999. DVI stands for Digital Visual Interface. DVI is in the process of replacing VGA as the most common way to connect monitors to computers. DVI was created to provide a standard way to transfer an image in digital form rather than in the analog form used by VGA. DVI is used almost exclusively in LCD panels. CRTs which accept DVI digital inputs are extremely rare. The CRTs which support DVI are usually high-end monitors which are trying to avoid image quality degradation in the VGA cable by transmitting the data digitally. The DVI connector also optionally supports analog video signals. There is more information about DVI on this page.

EDID

EDID stands for extended display identification data. When a video card wants to know about the capabilities of a monitor, it reads the EDID from the monitor. The EDID data contains information like the resolution and refresh rate of supported screen modes. It also tells whether the monitor is digital or analog as well as many other details about the monitor.

expansion card

A card which plugs into an expansion slot on the motherboard to add a device to the computer. Expansion cards can be things like video cards, network boards, sound cards, etc.

expansion slot

A connector on the motherboard which accepts an expansion card to add a device to the computer. The most common kinds of expansion slots are AGP, PCI, and PCI-Express.

GB/s

GB/s stands for gigabytes per second. A gigabyte is approximately a billion bytes (actually it's 1,073,741,824 bytes). So 1 GB/s is about a billion bytes per second.

GHz

GHz is short for gigahertz. A gigahertz is a billion (1,000,000,000) cycles per second. Various clock rates in a computer are measured in gigahertz. For example, a 3.2 GHz CPU runs at 3.2 billion (3,200,000,000) cycles per second.

gigabyte

A gigabyte is little more than a billion bytes (actually it's 1,073,741,824 bytes). The size of hard disks are often given in gigabytes.

GPU

GPU stands for graphics processing unit. This is the silicon chip on a display adapter which does the graphics calculations. Most of the GPUs are currently made by Intel, NVIDIA, or ATI. Other manufacturers include VIA, SiS, and Matrox.

graphics driver

Graphics driver is the same as display driver.

Hz

Hz is short for hertz. Hertz is the unit for cycles per second. For example, a video monitor with a screen refresh rate of 75 Hz refreshes the screen 75 times a second.

integrated graphics

Integrated graphics means that the hardware which displays images on the monitor is integrated into the motherboard. It's built into the motherboard in order to lower costs. Integrated graphics also tends to be slower than video cards and have less advanced functionality.

integrated video

Integrated video means that the hardware which displays images on the monitor is integrated into the motherboard. It's built into the motherboard in order to lower costs. Integrated video also tends to be slower than video cards and have less advanced functionality.

LCD

LCD stands for liquid crystal display. LCD computer monitors are the newer flat panel ones which use a flat LCD panel to display images. LCD panels are smaller, lighter, and consume less power than CRT monitors. LCD monitors running at their native resolution (or their native resolutions divided by 2, 3, etc.) display much sharper images than CRT monitors but LCDs display images poorly at other resolutions.

LED

LED stands for light emitting diode. An LED is a small solid-state light. Most of the small lights on a computer are LEDs because they are cheap and don't burn out.

megabyte

A megabyte is little more than a million bytes (actually it's 1,048,576 bytes). The amount of RAM in a computer is often given in megabytes.

MB/s

MB/s stands for megabytes per second. A megabyte is approximately a million bytes (actually it's 1,048,576 bytes). So 1 MB/s is about a million bytes per second.

MHz

MHz is short for megahertz. A megahertz is a million (1,000,000) cycles per second. Various clock rates in a computer are measured in megahertz. For example, a 400 MHz GPU on a video card runs at 400 million (400,000,000) cycles per second.

motherboard

This is the main circuit board in your computer. It holds the CPU, the main memory, and the expansion slots.

overclock

Setting the clock rate of a chip higher than its intended value is called overclocking. This increases the speed of the chip but it also heats it up and can cause stability problems. It may even shorten the lifespan of the chip if it is overclocked too much. People overclock to make parts of their computers run faster without having to buy the more expensive chips which officially support the higher clock rates.

PCI

A kind of expansion slot. PCI stands for peripheral component interconnect. PCI slots can be used to add all kinds of devices to a computer including video cards, network boards, and disk controllers. PCI expansion slots cannot accept PCI-Express expansion cards.

PCI-Express

A kind of expansion slot. PCI-Express is a faster kind of slot than PCI. PCI-Express slots can be used to add all kinds of devices to a computer including video cards, network boards, and disk controllers. There are different sizes of PCI-Express expansion slots. PCI-Express x16 slots are used for video cards. PCI-Express x1 slots are used for many different kinds of devices. PCI-Express expansion slots cannot accept PCI expansion cards.

PCI-Express x16

This is the kind of PCI-Express expansion slot which is usually used to hold video cards. The "x16" part refers to the number of lanes. This kind of slots has 16 lanes. Each lane can read data at a peak of 250 MB/s and write at 250 MB/s simultaneously. As a result, a PCI-Express x16 slots can read at 4 GB/s and write at 4 GB/s.

pixel

Pixel is short for picture element. You can make a pretty good version of an image by creating a two dimensional array of small squares and storing a single color in each square. Each of the small squares is a pixel. An image with a resolution of 640 by 480 pixels is made up of 640 columns where each column is 480 pixels tall. That image contains 640 times 480 pixels or 307,200 pixels. The more pixels that are in an image, the sharper it is. A 1280 by 960 version of an image has twice as many columns and twice as many rows and looks much sharper than a 640 by 480 image.

RAM

RAM is just computer memory. Your computer contains lots of RAM chips where it stores information. The main memory in your computer is probably stored on memory sticks which contain 256MB or more apiece. Your video card also contains RAM chips where it stores information used to draw images on your monitor. RAM actually stands for random access memory but that's not important for its current usage.

reboot

Rebooting a computer means that the computer shuts down and then bootstraps the operating system again. Rebooting is done after you've made a change which requires restarting the operating system.

screen refresh rate

The screen image you see on a computer monitor is repeatedly redrawn many times a second. The rate at which the entire screen image is redrawn is called the screen refresh rate. It's generally expressed in cycles per second or hertz. CRTs display an image by shooting a beam of electrons at phospors on the front surface of the CRT tube. The phospors glow for a little while after being hit by the electrons. The phosphor image is bright after being drawn and then quickly fades. If the CRT image is redrawn too slowly then the image flickers noticeably. For a standard computer CRT, a 60 Hz refresh rate flickers badly enough to cause eyestrain in most people. 75Hz barely flickers and 85Hz is considered flicker free. LCDs display their screen image using a completely different technology which doesn't flicker. There's still some benefit in increasing an LCDs refresh rate if you want it to display quickly changing images as seen in many games. But, for the most part, 60Hz is an acceptable refresh rate for LCDs.

screen resolution

The screen image displayed on a computer monitor is actually a two dimensional array of pixels. The number of pixels used to display an image is called the screen resolution. It is usually expressed as the number of horizontal pixels (the number of columns of pixels) and the number of vertical pixels (the number of rows of pixels). For example a screen resolution of 640 X 480 (pronounced "640 by 480") is 640 pixels wide and 480 pixels tall. More pixels produce a sharper image so an 800 X 600 screen resolution is sharper than 640 X 480.

underclock

Setting the clock rate of a chip lower than its intended value is called underclocking. This makes the chip run cooler and slows it down. This is usually down to try to troubleshoot problems. If underclocking solves a problem, then it usually means the chip is damaged or overheating.

unzip

Unzipping is short for the process of uncompressing a file which has been compressed with the ZIP compression method. Windows XP has built-in zip file decompression software. One way to unzip in XP is to right-click on the zip file and then select "Extract All...". That allows you to select a destination directory and then uncompress the file(s) into it. If the zip file looks like a directory, then double-clicking on the zip file opens the file up as a directory which allows access to the compressed file(s). You can also use many free or shareware software utilities to compress and decompress zip files. WinZip and WinRAR are two popular choices.

VGA

VGA is the long-used video standard which was introduced in 1987. VGA stands for Video Graphics Array. VGA actually is the name of the main chip on the original VGA video card introduced by IBM. Over time, VGA has become a more general term refering to a particular video card standard which includes the VGA output connector. The VGA connector is still commonly used but is in the process of being supplanted by the newer DVI connector. The VGA connector is sometimes called an HD-15 connector or a DSub-15 connector. There is more information about VGA on this page.

video board

Video board is the same as video card

video card

A video card is an expansion card which displays images on your monitor.

video driver

Video driver is the same as display driver.

video RAM

Video RAM refers to the memory chips on a video card. Current (2006) video cards commonly have from 64MB to 512MB of video RAM.

zip file

A zip file is a file which has been compressed with the ZIP compression method. Decompressing a zip file is refered to as unzipping. Windows XP has built-in zip file decompression software. One way to unzip in XP is to right-click on the zip file and then select "Extract All...". That allows you to select a destination directory and then uncompress the file(s) into it. If the zip file looks like a directory, then double-clicking on the zip file opens the file up as a directory which allows access to the compressed file(s). You can also use many free or shareware software utilities to compress and decompress zip files. WinZip and WinRAR are two popular choices.