Malware is a kind of software program whose name derives from the words "malicious" and "software" -- and that is just what it is. Malware is typically transmitted via the Internet or a computer network, and can damage or destroy the infected computer or network. Malware comes in several forms: viruses, worms, zombies, Trojan Horses, and spyware. Each form is engineered differently, but all are destructive. Software is available to protect against malware.

Master Hierarchy

A special hierarchy used to grant users specific access privileges to view only the account that belong to the branches of the hierarchy that you specify. If you have created only one hierarchy, it is by default the Master Hierarchy.

Megabits Per Second (Mbps)

A unit of measure that tells how many megabits of data can be transferred from one computer to another in a second (a bit being the smallest unit of data and megabit being about 1 million bits). Typically used to measure the rate at which information travels over the Internet.

Megabyte (M or MB)

A unit of measure for a chunk of data totaling about 1 million bytes (1,048,576 bytes, or 2 to the 20th power, to be exact, because bytes are calculated as binary numbers, based on the number 2). The following table shows standard measures of data based on bytes:

Term Abbreviation Approximate Value Precise Binary Value
Byte B 8 bits  
Kilobyte K or KB 1,000 bytes 1,024 bytes or 2 to the 10th power
Megabyte M or MB 1 million bytes 1,048,576 bytes or 2 to the 20th power
Gigabyte G or GB 1 billion bytes 1,073,741,824 bytes or 2 to the 30th power
Terabyte TB 1 trillion bytes 1,099,511,627,776 bytes or 2 to the 40th power
Moving Pictures Experts Group (MPEG)

MPEG is a standard for compressing sound and movie files into a format for downloading -- or even streaming it live -- across the Internet. It is one of three major video technologies for computing. (The others are Video for Windows and QuickTime.) There are three versions of MPEG. MPEG-1 moves video and sound data at 150 kilobytes per second (the same rate as a single-speed CD-ROM drive), which it manages by taking key frames of video and filling only the areas that change between the frames. But MPEG-1 produces only adequate-quality video, far below that of standard TV. MPEG-2 compression improves things dramatically, providing near-laserdisc clarity with a CD-quality stereo soundtrack. For that reason, modern video delivery media, such as digital satellite services and DVD, use MPEG-2. MPEG-4 combines the technology of the other two with that of QuickTime and uses narrower bandwidth.

Multi-purpose Internet Mail Extensions (MIME)

MIME is a way to extend the power of the Web to handle graphics, sound, multimedia, and non-text (non-HTML-based) data, or in the case of email, to handle text that is based on the ASCII computer language.