A network is a group of computers that are connected with each other and able to send and receive data. The computers within a network are sometimes referred to as ‘nodes’ or ‘workstations’ and the way they are connected to each other is referred to as the network’s ‘topology’.
A typical type of network is the LAN [Local Area Network], where all nodes are connected to a dedicated server used for disk storage and shared applications. Some smaller organizations, by contrast, may have a peer-to-peer network: in this case, all computers on the network are connected to each other, but there is no dedicated server.
In larger organizations, which may be geographically dispersed, several LANs (at each physical site, for example) may be connected to a WAN [Wide Area Network], often using the public telecommunications infrastructure.
The Internet can be seen as a ‘super network’ that uses public telecommunications infrastructure to combine countless individual networks through the common use of the TCP/IP protocol.
NTFS is the file system used by Microsoft® Windows® NT, Windows® 2000 and Windows® XP. It was developed after the FAT file system implemented in MS DOS and provides more efficient and secure methods for storage and retrieval of files (including support for very large files, integrated file compression, a more efficient directory system and access control for specific files). By contrast with the FAT system, information about each file is stored in the clusters belonging to that file (although there is also a MTF [Master File Table] that keeps track of all the clusters on the disk).
Synonyms: Worm, Computer worm, Email worm, Internet worm
Worms are generally considered to be a subset of viruses, but with key differences. A worm is a computer program that replicates, but does not infect other files: instead, it installs itself on a victim computer and then looks for a way to spread to other computers.
From a user’s perspective, there are observable differences. In the case of a virus, the longer it goes undetected, the more infected files there will be on the victim computer. In the case of a worm, by contrast, there is just a single instance of the worm code. Moreover, the worm’s code is ‘self-standing’, rather than being added to existing files on the disk.
Like viruses, worms are often sub-divided according to the means they use to infect a system. E-mail worms are distributed as attachments to e-mail messages, IM worms are attached to messages sent using instant messaging programs (such as IRC or ICQ). P2P [peer-to-peer] worms use file-sharing networks to spread. Network worms spread directly over the LAN [Local Area Network] or across the Internet, often making use of a specific vulnerability.
The term ‘worm’ was coined by sci-fi writer John Brunner in his 1975 novel Shockwave Rider. The hero, a talented programmer, created self-replicating computer programs that tunneled their way through a worldwide network.