Glossary of Terms

A list of technical terms commonly used in the field of computer sciences and computer forensics is provided below. Some of the definitions listed here were found in Webopedia, an online resource on the World Wide Web.


Short for "Web browser," this software application can locate and display Web pages. The two most popular browsers are Netscape Navigator and Microsoft Internet Explorer. Both of these are graphical browsers, which means that they can display graphics as well as text.

Campus-Area Network (CAN)

The computers are within a limited geographic area, such as a campus or military base.

Central Processing Unit (CPU)

The CPU is the brains of the computer. Sometimes referred to as the processor or central processor, the CPU is where most calculations take place.

Cipher Text

Data that has been encrypted. Cipher text is unreadable until it has been converted into plain text (decrypted) with a key. Only a password or table that can decipher encoded data.

Circuit Board

Sometimes abbreviated as PCB or printed circuit board, a circuit board is a thin plate on which chips and other electronic components are placed. Computers consist of one or more boards, often called cards or adapters.

Computer Forensics

The application of computer investigation and analysis techniques to determine potential legal evidence.


A cookie is a message given to a Web browser by a Web server. Cookies are used to identify users and can possibly be used to prepare Customized Web pages for them. Cookies can not spread viruses, not can they access the hard drive.


To remove or erase, e.g. deleting a character means removing it from a file or erasing it from the display screen or a disk. A common misconception when deleting files is that they are also removed from the hard drive. However, data can still be retrieved from the hard drive even after the files have been deleted. The only way to completely erase a file with no trace is to overwrite the data.

Digital Storage Media

An electronic device, or the media that fits into an electronic device, that stores bits of digital information otherwise known as "data." Many electronic devices fit into this category including laptops, personal computers, computer networks, cellular phones, personal digital assistants (aka Palm Pilots), MP3 players, CD players, video cameras, and digital cameras.

All of these devices store data in a variety of formats, including: audio files (voice, telephone calls, music), video, pictures (diagrams, charts, photographs), and virtually any kind of document. Many of these same devices can store large amounts of data on small, portable media such as hard disks, floppy disks, optical disks, tapes, Zip disks and drives, or memory sticks.

Digital Tape

Relatively inexpensive and can have very large storage capacities, but they do not permit random access of data. Video cameras can record several hours of live full-motion video on a single tape. Tapes are also used on computer systems to backup entire workstations or servers and vary in capacity from 2GB to 40GB.


To copy data (usually an entire file) from a main source to a peripheral device. The term is often used to describe the process of copying a file from an online service or bulletin board service to one's own computer. Downloading can also refer to copying a file from a network file server to a computer on the network.


The translation of data into a secret code. Encryption is the most effective way to achieve data security. To read an encrypted file, you must have access to a secret key or password that enables you to decrypt it. Unencrypted data is called plain text; encrypted data is referred to as cipher text.

Floppy disks

Relatively slow and have a small capacity, but they are portable, inexpensive, and universal. Floppy disks can retain up to 1.4MB of data.

Hard disks

Very fast and with more capacity than floppy disks, but also more expensive. Some hard disk systems are portable (removable cartridges), but most are not. Current hard disk capacities vary from 10GB to +100GB.


Refers to objects that you can actually touch, like disks, disk drives, display screens, keyboards, printers, boards and chips.

Home-Area Network (HAN)

A network contained within a user's home that connects a person's digital devices.


The Internet is a massive network of networks or a networking infrastructure. It connects millions of computers together globally, forming a network in which any computer can communicate with any other computer as long as they are both connected to the Internet. Information that travels over the Internet does so via a variety of languages known as protocols.

IP Address

A name for a computer device on a Transmission Control Protocol (TCP)/Internet Protocol (IP) network. The TCP/IP is built into the operating system, and it is how data is transmitted from the Internet to the user.

Local-Area Network (LAN)

A computer network that spans a relatively small area. For example, most LANs are confined to a single building or group of buildings.


Objects on which data can be stored. These include hard disks, floppy disks, CD-ROMS and tapes. In computer networks, media refers to the cables linking workstations together.

Memory Sticks

This is a relatively new form of digital storage that works with a wide variety of consumer electronic devices including: digital cameras, digital video cameras, and Sony MP3 audio recorder. These memory cards are extremely compact (approx. 1" x 2") and come in various storage capacities from 16MB to 128 MB.

Metropolitan-Area Network (MAN)

A data network designed for a town or city.


A group of two or computer systems that are linked together.

Operating System

Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.

For large systems, the operating system has even greater responsibilities and powers. It ensures that different programs and users running at the same time do not interfere with each other. The operating system is also responsible for security, so that unauthorized users do not access the system.

Optical disks (CD-ROMs, Mini CDs, DVD)

Unlike floppy and hard disks, which use electromagnetism to encode data, optical disk systems use a laser to read and write data. Optical disks have very large storage capacity, but they are not as fast as hard disks. The most common form of optical disk that you will encounter is the CD-ROM. The most common variety of CD can store up to 650MB (megabytes) or 74 minutes of audio recording time. A single CD-ROM has the storage capacity of 700 floppy disks, enough memory to store about 300,000 text pages. CD-ROMs are particularly well-suited to information that requires large storage capacity. This includes color large software applications, graphics, sound, and especially video.

DVD disks are also commercially available at this time and can be used to record up to 4.7GB of video data on a disk that is the same size/shape of a traditional CD.

Mini CDs are available that generally store 21 minutes of audio, or 50MB of data on a small surface roughly the size of a business card.


A secret series of characters that enable a user to access a file, computer or program. The password helps ensure that unauthorized users do not access the computers. Ideally, the password should be something that nobody could guess. In practice, most people choose a password that is easy to remember such as their name or their initials. This may be why it is relatively easy to break into most computer systems.


The rules and encoding specifications for sending data.

Secure Sockets Layer (SSL)

A protocol developed by Netscape for transmitting private documents via the Internet. SSL works by using a public key to encrypt data that is transferred over the SSL connection. Both Netscape Navigator and Internet Explorer support SSL, and many Web sites use the protocol to obtain confidential user information such as credit card numbers.


A computer or device on a network that manages network resources. For example, a file server is a computer and storage device dedicated to storing files. Any user on the network can store files on the server. A print server is a computer that manages one or more printers, and a network server is a computer that manages network traffic. A database server is a computer system that processes database queries.

Servers are often dedicated, meaning that they perform no other tasks besides their server tasks. On multiprocessing operating systems, however, a single computer can execute several programs at once. A server in this case could refer to the program that is managing resources rather than the entire computer.


Anything that can be stored electronically is software. Software exists as ideas, concepts, and symbols, and is often divided into two categories:

Text File

A file that holds text (word, sentences, paragraphs) and is usually stored as ASCII code. Most computers use ASCII codes to represent text which makes it possible to transfer data from one computer to another. Objects that are not text include graphics, numbers and program code.


To copy a file from your own computer to another computer.

Wide-Area Network (WAN)

A LAN that is connected to other LANs over any distance via telephone lines and radio waves.

World Wide Web

The Web is not the Internet, but it is related to it. The Web is actually a way of accessing information over the medium of the Internet.

Zip drive

A high-capacity floppy disk drive developed by Iomega ®. Zip disks are slightly larger than conventional floppy disks, and about twice as thick. They can hold 100, 250, or 750 MB of data. Because they're relatively inexpensive and durable, they have become a popular media for backing up hard disks and for transporting large files.



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