What is a computer

A computer is...

An electronic device that manipuates infor or data

USB (Universal Serial Bus) Port

Most desktop computers have several USB ports. These can be used to connect almost any type of device, including mice, keyboards, printers, and digital cameras. They will often appear on the front and back of the computer.

Page Up and Page Down

These scroll a document or webpage up or down.

Serial Port

This port is less common on today's computers. It was frequently used to connect peripherals like digital cameras, but it has been replaced by USB and other types of ports.

The Print Screen key takes a

picture of your screen (called a screenshot) that you can edit or save using a graphics program. Scroll Lock and Pause/Break are rarely used today, so some keyboards don't have them.

RAM is your system's

short-term memory. Whenever your computer performs calculations, it temporarily stores the data in the RAM until it is needed.

Audio In/Audio Out

Almost every computer has two or more audio ports where you can connect various devices, including speakers, microphones, and headsets.

Older monitors use

CRT (cathode ray tube) displays. CRT monitors are much larger and heavier, and they take up more desk space.

The function keys are labeled

F1 through F12. Some programs use these keys as shortcuts for common tasks. For example, in many programs, F1 opens the Help file.

There are many other types of ports, such as

FireWire, Thunderbolt, and HDMI.

Newer monitors usually have

LCD (liquid crystal display) or LED (light-emitting diode) displays. These can be made very thin, and they are often called flat-panel displays.

Audio In/Audio Out

Many computers include audio ports on the front of the computer case that allow you to easily connect speakers, microphones, and headsets without fumbling with the back of the computer.

Power Button

The power button is used to power the computer on and off.

Expansion Slots

These empty slots are where expansion cards are added to computers. For example, if your computer did not come with a video card, you could purchase one and install it here.

Home and end: These move the cursor to the beginning or end of the current line.

These move the cursor to the beginning or end of the current line.

PS/2

These ports are sometimes used for connecting the mouse and keyboard. Typically, the mouse port is green and the keyboard port is purple. On new computers, these ports have been replaced by USB.

Parallel Port

This is an older port that is less common on new computers. Like the serial port, it has now been replaced by USB.

Power Socket

This is where you'll connect the power cord to the computer.

Monitor Port

This is where you'll connect your monitor cable. In this example, the computer has both a DisplayPort and a VGA port. Other computers may have other types of monitor ports, such as DVI (digital visual interface) or HDMI (high-definition multimedia interface).

Ethernet Port

This port looks a lot like the modem or telephone port, but it is slightly wider. You can use this port for networking and connecting to the Internet.

Hardware is any part of your computer that has

a physical structure, such as the keyboard or mouse. It also includes all of the computer's internal parts, which you can see in the image below.

Many scanners are included as part of an

all-in-one printer, although you can also buy a separate flatbed or handheld scanner.

The main part of the keyboard includes the

alphanumeric keys (letters and numbers) and the spacebar.

Trackball: A trackball has a ball that

can rotate freely. Instead of moving the device like a mouse, you can roll the ball with your thumb to move the pointer.

Delete: This erases the

character to the right of the cursor.

The basic parts of a desktop computer are the

computer case, monitor, keyboard, mouse, and power cord. Each part plays an important role whenever you use a computer.

The back of a computer case has

connection ports that are made to fit specific devices. The placement will vary, and many companies have their own special connectors for specific devices. Some of the ports may be color coded to help you determine which port is used with a particular device.

The optical mouse uses an

electronic eye to detect movement and is easier to clean. The mechanical mouse uses a rolling ball to detect movement and requires regular cleaning to work properly.

A desktop case lies

flat on a desk, and the monitor usually sits on top of it.

The Tab key is used to create

indents in word processing programs. Also, if you are filling out a form online, you can use the Tab key to switch to the next field.

A server is a computer that serves up

information to other computers on a network. For example, whenever you use the Internet, you're looking at something that's stored on a server. Many businesses also use local file servers to store and share files internally.

Insert: This switches between

insert mode (which inserts new text without deleting anything) and overtype mode (which deletes text after the cursor as you type).

Software is any set of

instructions that tells the hardware what to do and how to do it. Examples of software include web browsers, games, and word processors.

A processor's speed is measured in

megahertz (MHz), or millions of instructions per second; and gigahertz (GHz), or billions of instructions per second. A faster processor can execute instructions more quickly. However, the actual speed of the computer depends on the speed of many different components—not just the processor.

The computer case is the

metal and plastic box that contains the main components of the computer, including the motherboard, central processing unit (CPU), and power supply. The front of the case usually has an On/Off button and one or more optical drives.

A tower case is tall and sits next to the

monitor or on the floor. All-in-one computers come with the internal components built into the monitor, which eliminates the need for a separate case.

Printers: A printer is used to print documents, photos, and anything else that appears on your screen. There are many types of printers, including i

nkjet, laser, and photo printers. There are even all-in-one printers, which can also scan and copy documents.

There are two main mouse types:

optical and mechanical.

The most basic computer setup usually includes the computer case, monitor, keyboard, and mouse, but you can plug many different types of devices into the extra ports on your computer. These devices are called

peripherals.

The central processing unit (CPU), also called a

processor, is located inside the computer case on the motherboard. It is sometimes called the brain of the computer, and its job is to carry out commands. Whenever you press a key, click the mouse, or start an application, you're sending instructions to the CPU.

The CPU is usually a two-inch ceramic square with a

silicon chip located inside. The chip is usually about the size of a thumbnail. The CPU fits into the motherboard's CPU socket, which is covered by the heat sink, an object that absorbs heat from the CPU.

The Escape (Esc) key allows you to

stop a function or action. For example, if a webpage is taking a long time to load, you can press the Escape key to stop loading it.

Your computer can

store, retrieve, and process data.

The motherboard is the computer's main circuit board. It's a

thin plate that holds the CPU, memory, connectors for the hard drive and optical drives, expansion cards to control the video and audio, and connections to your computer's ports (such as USB ports). The motherboard connects directly or indirectly to every part of the computer.

The Print Screen, Scroll Lock, and Pause/Break keys are at the

top-right corner of the keyboard.

Touchpad: A touchpad—also called a

trackpad—is a touch-sensitive pad that lets you control the pointer by making a drawing motion with your finger. Touchpads are common on laptop computers.

This short-term memory disappears when the computer is

turned off. If you're working on a document, spreadsheet, or other type of file, you'll need to save it to avoid losing it. When you save a file, the data is written to the hard drive, which acts as long-term storage.

The monitor works with a

video card, located inside the computer case, to display images and text on the screen. Most monitors have control buttons that allow you to change your monitor's display settings, and some monitors also have built-in speakers.

Optical Disc Drive

Often called a CD-ROM or DVD-ROM drive, this lets your computer read CDs and DVDs.

USB Ports

On most desktop computers, most of the USB ports are on the back of the computer case. Generally, you'll want to connect your mouse and keyboard to these ports and keep the front USB ports free so they can be used for digital cameras and other devices.