Glossary terms provided by TechTerms.com.
| Word | Description |
| BACK / FORWARD | Buttons in most browsers' Tool Button Bar, upper left. BACK returns you to the document previously viewed. FORWARD goes to the next document, after you go BACK. |
| Back-end | A type of program or process that is not directly accessed by a user. Often it will carry out its tasks independently of the front-end or user interface. For example, a user could request data from a database, not knowing that the data is refreshed on the back-end on a daily basis. |
| Backbone | A high-speed line or series of connections that forms a major pathway within a network. The term is relative as a backbone in a small network will likely be much smaller than many non-backbone lines in a large network. |
| Backdoor | A backdoor is a tool installed after a compromise to give an attacker easier access to the compromised system around any security mechanisms that are in place. |
| Backplane | As opposed to standard cabling schemes where flexible wires are used, a backplane refers to a rigid circuit board that will support higher connection speeds and more logic. For example, many SCSI systems today ship with small SCSI backplanes because the transfer rate of SCSI is getting high enough that standard cables are causing problems when connecting devices. Another example of a backplane is in network connection devices, such as large enterprise scale switches, routers, or PBXs. Some of these devices have a high- speed backplane, and you can plug a group of slower network connection devices into the high-speed backplane. |
| Backup | Backup 1. A recovery system or means to recover in the event of a disaster. 2. To take a copy of files (directories or data) so that these can be restored later if needed. Backups should always be taken regularly to protect against accidental deletion of files or hardware failure. Many applications generate a backup file as they work. For example most work processors can be configured to generate a backup file of the document they are working on, allowing the previous version to be recovered if necessary. However this type of backup will not protect against hardware failure, if the disk fails then you loose your original and the backup. A good backup scheme will ensure that files are copied to a separate medium (such as cd or tape) and physically moved to a different area, ideally to a different site. Moving a backup (or a copy of a backup) to an offsite location is referred to as an "offsite backup", and the advantage of maintaining an "offsite backup" is that it allows files to be recovered in the event of a disaster such as a fire that may destroy the entire building. 3. The copy of a file (or set of files or data) that has been taken. A backup may therefore be the copy of a file or it may refer to a disk, cd or tape that contains files (or data) that have been backed up. |
| Backup Mail Server | A secondary email server to which emails are delivered should the primary email server be offline. A backup email server will then forward emails to the primary email server once the primary email server comes back on-line. When an email server is down most sending email servers will retain the email and try sending again later. Generally most servers will give up and issue a non-delivery notification (NDR) to the sender after about two days (the actual time varies between servers). So even without a backup mail server emails will normally be delivered if the mail server is down for a short period of time. A backup mail server provides resilience where: The sending server has a very short timeout before giving up and issuing an NDR. The server will be down for a long period - as a guide anything over a day or so. In these scenarios a backup mail server will receive emails and ensure that they are delivered once the primary mail server comes back on-line. cf SMTP, MX Record. |
| Balance | The control for the level of sound coming out of the left or right speakers. If you turn the balance control all the way in either direction, you can isolate the sound to the left or right channel, which helps in troubleshooting whether both speakers are connected properly. Other than that, the balance control can fine-tune volume levels to compensate for sound conditions in the room. |
| Bandwidth | The amount of data that can be transmitted in a fixed amount of time. cf bps. |
| Banner Ad | Whether you like it or not, much of the Web is run by advertising. Just like television or radio, websites can offer free content by generating revenue from advertising. While you may get tired of Web ads from time to time, most people would agree that seeing a few advertisements here and there is better than paying a usage fee for each website. Perhaps the most prolific form of Web advertising is the banner ad. It is a long, rectangular image that can be placed just about anywhere on a Web page. Most banner ads are 468 pixels wide by 60 pixels high (468x60). They may contain text, images, or sometimes those annoying animations that make it hard to focus on the page's content. Regardless of the type of banner ad, when a user clicks the advertisement, he or she is redirected to the advertiser's website. |
| Bare metal environment | A virtual environment where the virtualization product is directly installed on physical hardware, acting like a host OS. The opposite of hosted environment. |
| Baseband | A baseband signal is an original transmission signal that has not be modulated, or has been demodulated to its original frequency. Most telecommunications protocols require baseband signals to be converted, or modulated, to a higher frequency so they can be transmitted over long distances. Therefore, the original baseband, or lowpass, signals are converted during the transmission process. When the signal arrives at the destination, it is demodulated so that the recipient receives the original baseband signal. Ethernet is an example of a protocol that does not require signal modulation, since it transmits data in baseband. Example: "Baseband signals must be modulated to higher frequencies for radio transmission." |
| BASIC | Beginners All-purpose Symbolic Instruction Code. A high level programming language which has been widely used, particularly since the advent of personal computers. Originally an unstructured programming language, the language has been adapted over the years to encompass new programming paradigms. |
| Basic Authentication | Basic Authentication is the simplest web-based authentication scheme that works by sending the username and password with each request. |
| Batch File | A batch file is a type of script that contains a list of commands. These commands are executed in sequence and can be used to automate processes. For example, some programs may include a batch file that executes a number of commands as the program starts up. A user can also create a custom batch file to automate tedious processes such as copying multiple directories or renaming several files at once. Batch files are run by the COMMAND.COM program, which is part of DOS and Windows. Therefore, batch files can only be run within the Windows operating system. Macintosh and Unix have other scripting tools, such as AppleScript and Unix shell commands, that can be used for similar tasks. Because batch files contain executable commands, it is important not to open unknown batch files on your hard disk or in e-mail attachments. File Extensions: .BAT, .CMD |
| Baud | In common usage the "baud" of a modem is how many bits it can send or receive per second. Technically, baud is the number of times per second that the carrier signal shifts value - for example a 1200 bit-per-second modem actually runs at 300 baud, but it moves 4 bits per baud (4 x 300= 1200 bits per second). |
| BBL | Online speak for “Be Back Later” |
| BBS | 1. Bulletin Board System. A system for storing information and messages that can be accessed by other computers. Typically accessed by dial-up, Bulletin Boards pre-date the internet. Bulletin Board Systems were a forerunner to Forums. 2. Chat abbreviation for: Be Back Soon. |
| Bcc (Blind Carbon Copy) | Stands for "Blind Carbon Copy." When you send an e-mail to only one person, you type the recipient's address in the "To:" field. When you send a message to more than one person, you have the option to enter addresses in the "Cc:" and "Bcc:" fields. "Cc" stands for "Carbon Copy," while "Bcc" stands for "Blind Carbon Copy." A carbon copy, or "Cc'd" message is an e-mail that is copied to one or more recipients. Both the main recipient (whose address is in the "To:" field) and the Cc'd recipients can see all the addresses the message was sent to. When a message is blind carbon copied, neither the main recipient nor the Bcc'd recipients can see the addresses in the "Bcc:" field. Blind carbon copying is a useful way to let others see an e-mail you sent without the main recipient knowing. It is faster than sending the original message and then forwarding the sent message to the other recipients. It is also good netiquette to use Bcc when copying a message to many people. This prevents the e-mail addresses from being captured by someone in the list who might use them for spamming purposes. However, if it is important that each recipient knows who your message was sent to, use carbon copy (Cc) instead. |
| BCP | 1. Best Current Practice. 2. Bridging Control Protocol. 3. Bulk Copy Process (or Bulk Copy Program). A utility provided with SQL Server databases for bulk copying of data, such as between a database and a file. 4. Business Continuity Plan. A contingency plan covering how a business should recover from potential disasters disaster and continue functioning. More commonly known as a disaster recovery plan (DRP). |
| BDC (backup domain controller) | One or more computers running Windows NT that act as a backup to the primary domain controller (PDC). These machines can authenticate security requests just like the primary domain controller, and will take over for the PDC if it is not available. However, a BDC will remain a BDC until it is manually promoted to a PDC by a domain administrator. With Active Directory Windows no longer requires the sometimes confusing primary and backup domain controllers, just domain controllers instead. |
| Beep | 1. Blocks Extensible Exchange Protocol. A set of building blocks for creating customised protocols. |
| Beep Code | When you turn on your PC–and all is well–you typically hear a single beep from your computer speaker, signaling that all is OK. If things are wrong–and the computer BIOS senses that things are wrong–a series of beeps will be emitted. This is the beep code. Based on the number of beeps, you can look up the meaning in your motherboard documentation and often diagnose the problem. Obvious things to check are whether your video card, processor, and/or memory are plugged in and seated properly. |
| Benchmarking | The process of measuring the performance of hardware or software in a specifically defined and strictly controlled environment. The benchmarking result is usually represented by a time or number rating that corresponds to how quickly certain tasks can be completed. The benchmark must be reproducible, of course, to have any meaning. |
| Beta | A term given to a product that isn’t ready for public consumption, but is good enough for a wider testing scope. Many companies publicly release their beta software to a fraction of their users to let them get experience with the new software while the company gets feedback on bugs and features. Also see Alpha |
| BGP | Border Gateway Protocol |
| Binary | Information consisting entirely of ones and zeros. Also, commonly used to refer to files that are not simply text files, e.g. images. |
| Binary code | Binary consists of a string of bits, with bits represented by 1s and 0s, e.g., 01010111000000001. The “bi” refers to base 2 mathematical representation (1s and 0s). |
| Binary Translation (BT) | Technique used by virtualization softwares to translate instruction set guest OSes send to virtual hardware in instruction set understandable by physical hardware. It's an alternative approach to paravirtualization. |
| BIND | Berkley Internet Name Domain. |
| Binhex | A method for converting non-text files (non-ASCII) into ASCII. This is needed because Internet e-mail can only handle ASCII. |
| Biometrics | Biometrics use physical characteristics of the users to determine access. |
| BIOS | Basic Input/Output System. The BIOS provides an interface between a computer's operating system and the computer's hardware. Unlike the operating system the BIOS is built into the computer and thus is always available. Many computers hold the BIOS in Flash and allow it to be upgraded. The BIOS will normally perform various diagnostic tests straight after power-up (see POST). At this point it is usual for a BIOS to allow you to enter a "BIOS Screen" to configure aspects of the BIOS (not every BIOS supports this). Whilst each BIOS may have a different way of invoking its "BIOS Screen" and the correct method should be stated in the manual, the following key combinations (at start-up) are common: DEL F2 F1 |
| Bit | Binary digIT. The fundamental unit of binary notation and storage. 0 (off) or 1 (on). There are 8 bits to a byte. |
| Bit rate | An alternate name for bits per second (bps). |
| BitTorrent | BitTorrent is a peer-to-peer (P2P) file sharing protocol designed to reduce the bandwidth required to transfer files. It does this by distributing file transfers across multiple systems, thereby lessening the average bandwidth used by each computer. For example, if a user begins downloading a movie file, the BitTorrent system will locate multiple computers with the same file and begin downloading the file from several computers at once. Since most ISPs offer much faster download speeds than upload speeds, downloading from multiple computers can significantly increase the file transfer rate. In order to use the BitTorrent protocol, you need a BitTorrent client, which is a software program that accesses the BitTorrent network. The client program allows you to search for files and begin downloading torrents, which are in-progress downloads. Most BitTorrent clients allow you to resume torrents that have been paused or stopped. This can be especially helpful when downloading large files. |
| BL | 1. Black List. See Blacklist for details. 2. Boundary Layer. In a GIS context a boundary layer is a feature layer on a map which contains boundaries (for example district or regional boundaries). In other contexts a boundary layer is the surface on which two boundaries meet. For example the surface of the sea is the boundary layer between sea-water and air. 3. Back Link. A link to a web page from another. Back links represent those pages (or specifically the links on those pages) that link to a given page. Back Links are also known as inbound links. 4. Block List. A list of IP addresses from which email addresses should be blocked. See DNSBL for details. |
| Black hat | A malicious hacker. If a hacker finds a security hole and exploits it or lets others know about it before letting the people affected by the hole know about it, that hacker is described as a black hat hacker. This term comes from cowboy movies, where the bad guy would wear a black hat. |
| Blacklist | Blacklist A list of disapproved people, companies or items. Companies may refuse to deal with individuals or other companies that have been blacklisted. SPAM filters will often maintain a blacklist, which holds e-mail addresses from which any e-mail is to be considered SPAM. Also sometimes referred to as a "Stop List". Sometimes abbreviated to simply BL. |
| Blade | A hot-pluggable motherboard, equipped with processors, memory and disks for use in a Blade Server. |
| Blade Server | An emerging modularized server configuration made by a standard rack featuring an embedded networking subsystem and several bays, where blades can be plugged while the system is turned on. |
| Block Cipher | A block cipher encrypts one block of data at a time. |
| Block Mode | A setting in the computer BIOS relating to IDE hard drives. The setting determines the type of Logical Block Addressing that will be used to translate large hard drives properly to the computer BIOS. On most machines with up-to-date BIOSes, you can set this to “Auto” and have hard drives recognized with no further specification on your part. If that doesn’t work, you may need to tinker with other settings or use the software provided by the hard drive manufacturer for software translation. |
| BLOG or WEB LOG | A blog (short for "web log") is a type of web page that offers a series of posted items (short articles, photos, diary entries, etc.). Blogs usually include a searchable archive of old postings. Blogs have become a common medium for communication in professional, political, news, trendy, and other specialized web communities. Many blogs provide RSS feeds, to which one can subscribe and receive alerts to new postings in selected blogs. |
| Blu-ray | Blu-ray is an optical disc format such as CD and DVD. It was developed for recording and playing back high-definition (HD) video and for storing large amounts of data. While a CD can hold 700 MB of data and a basic DVD can hold 4.7 GB of data, a single Blu-ray disc can hold up to 25 GB of data. Even a double sided, dual layer DVD (which are not common) can only hold 17 GB of data. Dual-layer Blu-ray discs will be able to store 50 GB of data. That is equivalent to 4 hours of HDTV. Blu-ray discs can hold more information than other optical media because of the blue lasers the drives use. The laser is actually blue-violet, but "Blu-ray" rolls off the tounge a little easier than "Blu-violet-ray." The blue-violet laser has a shorter wavelength than the red lasers used for CDs and DVDs (405nm compared to 650nm). This allows the laser to focus on a smaller area, which makes it possible to cram significantly more data on a disc the same size as a CD or DVD. Proponents of the Blu-ray format say they expect Blu-ray devices to replace VCRs (thank goodness) and DVD recorders as more people make the transition to HDTV. |
| Bluetooth | This wireless technology enables communication between Bluetooth-compatible devices. It is used for short-range connections between desktop and laptop computers, PDAs (like the Palm Pilot or Handspring Visor), digital cameras, scanners, cellular phones, and printers. Infrared once served the same purpose as Bluetooth, but it had a number of drawbacks. For example, if there was an object placed between the two communicating devices, the transmission would be interrupted. (You may have noticed this limitation when using a television remote control). Also, the Infrared-based communication was slow and devices were often incompatible with each other. Bluetooth takes care of all these limitations. Because the technology is based on radio waves, there can be objects or even walls placed between the communicating devices and the connection won't be disrupted. Also, Bluetooth uses a standard 2.4 GHz frequency so that all Bluetooth-enabled devices will be compatible with each other. The only drawback of Bluetooth is that, because of its high frequency, its range is limited to 30 feet. While this is easily enough for transferring data within the same room, if you are walking in your back yard and want to transfer the address book from your cell phone to your computer in your basement, you might be out of luck. However, the short range can be seen as a positive aspect as well, since it adds to the security of Bluetooth communication. |
| BMP | Bitmap file; a common image format on Windows computers. Files of this type usually have the suffix ".bmp" as part of their name. |
| Bookmark | Similar to a real-life bookmark, an Internet bookmark acts as a marker for a Web site. (In Internet Explorer, they're called "Favorites".) When using a Web browser, you can simply select a bookmark from the browser's Bookmarks menu to go to a certain site. This way, you don't have to go through the redundant process of typing in the Internet address each time you visit one of your favorite sites. Also, who remembers those 200-character addresses anyway? In most browsers, to create a bookmark, you simply choose "Add Bookmark" from the Bookmarks menu when you're at a page that you'd like to bookmark. Woah, four "bookmarks" in one sentence. That's what happens with words that serve as both nouns and verb. So, now that you know how to create a bookmark, be sure to bookmark this website! =) |
| Boolean | This is the logic that computers use to determine if a statement is true or false. There are 4 main boolean operators: AND, NOT, OR, and XOR. Below are some examples of how the 4 operators work: x AND y retuns True if both x and y are true, otherwise the expression returns False. NOT x returns True if x is false (or null) and False if x is true. x OR y returns True if either x or y or both are true; only if they are both false will it return False. x XOR y returns True if either x or y are true, but not both. If x and y are both true or false, the statement will return False. While boolean expressions are what drive the CPUs in computers, they can also be used by computer users. For example, when searching for information on the Web, many search engines accept boolean operators in the search phrases (i.e. "Yamaha AND piano NOT motorcycle"). Programmers often use boolean expressions in software development to control loops and variables as well. |
| Boot | When you boot a football, you kick it really far. When you boot a computer, you simply turn it on. Kicking your computer really far is not recommended, though you may be tempted to do so at times. The term "boot" comes from the word "bootstraps," which people at one time used to get their boots on. Likewise, "booting" a computer gets it up and running. In simple terms, to boot a computer is to turn it on. Once the computer's power is turned on, the "boot process" takes place. This process involves loading the startup instructions from the computer's ROM, followed by loading the operating system from the current boot disk. The boot disk is usually an internal hard drive, but can also be an external drive, a CD or DVD-ROM, or even a floppy disk. Once the operating system software is loaded, the boot process is complete and the computer is ready to be used. |
| Boot Disk | A boot disk is actually not a computer disk in the shape of a boot. If it was, most disk drives would have a difficult time reading it. Instead, a boot disk is a disk that a computer can start up or "boot" from. The most common type of boot disk is an internal hard drive, which most computers use to start up from. The operating system installed on the hard drive is loaded during the boot process. However, most computers allow you to boot from other disks, including external Firewire hard drives, CD-ROMs, DVD-ROMs, and floppy disks. In order to function as boot disks, these disks need to have an operating system installed that is understandable by the computer. This can either be a full-blown operating system like Windows or Mac OS X, or a small utility operating system, such as Norton Utilities or DiskWarrior. CD and DVD boot disks are often used to start up a computer when the operating system on the internal hard drive won't load. This can happen when bad data blocks or other errors occur on the disk. By running a disk repair utility from the CD or DVD, you can often fix the hard drive and restart from it, using the full operating system. |
| Boot Record (Master Boot Record) | The first sector on a hard disk or other disk media. When a computer boots up it searches for a master boot record wherever the BIOS tells it to (usually the master hard drive on the first IDE channel, but this can also be checked for in CD/DVD drives and floppy drives) and, based on what the master boot record says, loads up an operating system. Thus, if the master boot record becomes corrupt or is tampered with by a virus, it can cause your computer to be unable to boot. |
| Boot Record Infector | A boot record infector is a piece of malware that inserts malicious code into the boot sector of a disk. |
| Boot Sector | boot sector is the first section of a hard drive or other data storage media. It contains the master boot record (MBR) which is accessed by the computer during the boot sequence. The boot sector may also include a partition map, which defines each disk partition. |
| Boot Sequence | Each time a computer boots up, it goes through an initial series of processes. This sequence of events is aptly named a "boot sequence." During the boot sequence, the computer activates the necessary hardware components and loads the appropriate software so that a user can interact with the machine. The boot sequence starts by accessing the the computer's BIOS on Windows PCs or the system ROM on a Macintosh. The BIOS and ROM contain basic instructions that tell the computer how to boot up. These instructions are then passed to the computer's CPU, which begins loading information into the system RAM. Once a valid boot disk or startup disk is found, the computer begins loading the operating system into the system memory. After the operating system finishes loading, the computer is ready to be used. The boot sequence can take anywhere from a few seconds to several minutes, depending on the computer's configuration. If the system is booting from a CD or DVD, the boot time may be significantly longer than if the computer is booted from a hard drive. Also, if your computer was turned off unexpectedly, the boot time might increase since the system may perform some additional checks to make sure everything is OK. |
| BootP (Bootstrap Protocol) | This protocol is the basis for DHCP. It allows a client computer to receive an IP address from a BootP server without having a static IP address defined beforehand on the client machine. |
| Bootstrap | This either refers to a small piece of intermediate code that will boot up an operating system, or the act of building something without help. See also Bootstrapping |
| Bootstrap Protocol (BootP) | his protocol is the basis for DHCP. It allows a client computer to receive an IP address from a BootP server without having a static IP address defined beforehand on the client machine. |
| Bootstrapping (v. to bootstrap) | The process of developing something without reliance on outside help such as investor money. It’s referred to often today, and often in the Dot-Com heyday, to describe website designers and entrepreneurs who effectively start their own companies on the Web with only their own investment. |
| Border Gateway Protocol (BGP) | The protocol used by the core routers on the Internet to route TCP/IP packets. BGP replaces the older Exterior Gateway Protocol. Core routers use BGP exchange routing information to determine optimal routing paths and also exchange TCP/IP data packets. |
| Bot | hort for web-robot, search-bot, robot or info-bot. A program that searches (trawls) the internet for information. Search engines use bots (search-bot) to gather information that the search engine uses to respond to search queries. A harvester-bot is used spammers to harvest e-mail addresses from web pages. |
| Bottleneck | Part of a system that limits the performance of the system. This term was derived from the neck of a bottle, which limits the flow of liquid due to the smaller circumference of the neck as compared to the wider body of the bottle. Often you will hear of people attempting to find and eliminate the bottlenecks in their computer systems or networks. This is certainly a helpful practice if the bottleneck is slowing things down inordinately, but as soon as you remove one bottleneck from a system remember that something else immediately becomes the bottleneck. For example, if you get a faster processor to speed up your 3D video, the 3D video card may be the bottleneck afterwards. |
| Bounce | The term "bounce" has several different IT related meanings, yet none of them include bouncy balls. The most common definition of bounce used in the computer world refers to e-mail messages. 1. Returning E-mail When you send an e-mail message to another person, the mail server processes the message and delivers it to the appropriate user's mailbox. For example, if you send a message to "mrman@mail.com," the mail.com server looks for a user named "mrman" to deliver the message to. If the user does not exist, the mail server may bounce the message back to the sender, saying "Sorry, that user does not exist." These messages often come from "Mail Delivery Subsystem" and have a subject line that reads "Returned mail: see transcript for details." If you receive a bounced message, you may want to check the e-mail address you sent the message to and make sure it was typed correctly. If the address is correct, it may help to read the body of the bounced message for more details. The transcript may say something like "User quota over limit," which means the recipient has reached his or her e-mail quota and must delete some messages and/or attachments in order to receive new mail. If this is the case, you may want to call the person or use an alternative e-mail address to let the person know he or she has some Inbox maintenance to do. 2. Restarting a Computer The term "bounce" can also describe the process of rebooting or restarting a computer. For example, a workstation may need to be bounced after installing new software. Similarly, a Web server may be bounced if websites hosted on the server are not responding correctly. 3. Exporting Audio "Bounce" can also describe the process of exporting several tracks in an audio mix to one mono track or two stereo tracks. This helps consolidate audio tracks after they have been mixed. Bouncing audio tracks limits the need for processing power since the computer only has to process one track instead of all the tracks individually. Digital Performer is the primary audio software program that uses bouncing to export audio. 4. Hiding a Network Connection Finally, "bouncing" can also be used in networking to describe a method of hiding the source of a user's network connection. This type of bouncing is often abbreviated "BNC." Someone who bounces his network connection is called a "bouncer," though this is not the same person who checks your ID at the bar. |
| Boxed Processor | A microprocessor that is sold singly in a retail box, like something you would buy at a store. This compares to just buying a processor that some OEM takes out of a bulk box of 1,000 processors and throws in a static bag for you to take home. Boxed processors typically come with multi-year warranties directly from the manufacturer. |
| BPS | Bits Per Second. Also known as bit rate. Used when specifying connection speeds across networks. When calculating the maximum throughput across a network remember that network communications itself has some overhead, so as a rule of thumb therefore divide by 10 to get the number of bytes that this equates to. For typical connection speeds this equates to: Speed Maximum achievable throughput 28.8Kbps 2.8 K-bytes per second 56Kbps 5.6 K-bytes per second 10Mbps 976 K-bytes per second (almost 1MB a second) 100Mbps 9.5 M-bytes per second (almost 10MB a second) Actual throughput rates may be less than this because of other factors such as other network traffic. |
| BRB | Online speak for “Be Right Back” |
| Brick and Mortar | A store or business that either doesn’t have a Web presence or has mainly physical locations as opposed to websites. Bricks and mortar are common building materials. |
| Bridge | When a road needs to extend across a river or valley, a bridge is built to connect the two land masses. Since the average car cannot swim or fly, the bridge makes it possible for automobiles to continue driving from one land mass to another. In computer networking, a bridge serves the same purpose. It connects two or more local area networks (LANs) together. The cars, or the data in this case, use the bridge to travel to and from different areas of the network. The device is similar to a router, but it does not analyze the data being forwarded. Because of this, bridges are typically fast at transferring data, but not as versatile as a router. For example, a bridge cannot be used as a firewall like most routers can. A bridge can transfer data between different protocols (i.e. a Token Ring and Ethernet network) and operates at the "data link layer" or level 2 of the OSI (Open Systems Interconnection) networking reference model. |
| Bridged networking | A type of network connection between a virtual machine and the rest of the world. Under bridged networking, a virtual machine appears as an additional computer on the same physical Ethernet network as the host. See also Host-only Networking. |
| Broadband | Generally refers to connections to the Internet with much greater bandwidth than you can get with a modem. There is no specific definition of the speed of a "broadband" connection but in general any Internet connection using DSL or a via Cable-TV may be considered a broadband connection. |
| Broadcast | To simultaneously send the same message to multiple recipients. One host to all hosts on network. |
| Broadcast Address | An address used to broadcast a datagram to all hosts on a given network using UDP or ICMP protocol. |
| Browser | Short for Web browser, a software application used to locate and display Web pages. The two most popular browsers are Microsoft Internet Explorer and Firefox. Both of these are graphical browsers, which means that they can display graphics as well as text. In addition, most modern browsers can present multimedia information, including sound and video, though they require plug-ins for some formats. |
| browser sniffing | Browser sniffing describes the process by which a Web site detects which versions of various browsers users are running, in order to determine whether or not they can access certain Web site features. Browser sniffing--usually accomplished with JavaScript--can also be used to detect whether or not a user has a specific plug-in required to access the site (such as Macromedia's Flash or RealNetworks' RealPlayer). |
| Brute Force | A cryptanalysis technique or other kind of attack method involving an exhaustive procedure that tries all possibilities, one-by-one. |
| BSOD | Blue Screen of Death Terminal error screen displayed by Microsoft Windows, not normally recoverable except by a reboot. Also known as BSOD or a Stop Screen. A blue screen will display a STOP error code, which may give some indication as to the cause. Relevant links: |
| BSOD (Blue/Black Screen of Death) | A Windows error message that is shown on a screen with a blue background. In Windows NT/2000/XP, this type of message causes the computer to stop completely, and is usually caused by improperly written hardware drivers or faulty hardware. Other BSODs can occur in different versions of Windows (95/98/Me) as well, but are not always as disastrous. Less frequently, black screens of death (also BSOD) are referred to as well during a complete system crash which may or may not have anything to do with the Windows OS. |
| BSSID | Basic Service Set Identification. The BSSID is the identifying name of an ad-hoc wireless network. BSSID is one type of SSID (the other being ESSID). |
| BST | British Summer Time. In the UK, the period between the last Sunday in March through to the last Sunday in October when the clocks are moved forward by one hour (at 1am in the morning). cf GMT and DST. BST = GMT + 1, so 16:00 GMT = 17:00 BST. |
| BTU | British Thermal Unit. One BTU is defined as the energy required to increase the temperature of one pound of water by one degree Fahrenheit. BTUs are typically used to rate air conditioners (and some heaters). To convert from BTUs to KWs: use 1 watt = 3.4129BTUs. This means that for typical air-conditioners: BTUs approx watt equivalent 6000 1.8KW 8000 2.3KW For air conditioners (AC) the typical power consumption will be less than half their cooling rating. As a guide: 1 person approximates to 500 BTU and likewise one PC approximates to 500 BTU. |
| BTW | Abbreviation: By The Way. |
| Buffer | buffer contains data that is stored for a short amount of time, typically in the computer's memory (RAM). The purpose of a buffer is to hold data right before it is used. For example, when you download an audio or video file from the Internet, it may load the first 20% of it into a buffer and then begin to play. While the clip plays back, the computer continually downloads the rest of the clip and stores it in the buffer. Because the clip is being played from the buffer, not directly from the Internet, there is less of a chance that the audio or video will stall or skip when there is network congestion. Buffering is used to improve several other areas of computer performance as well. Most hard disks use a buffer to enable more efficient access to the data on the disk. Video cards send images to a buffer before they are displayed on the screen (known as a screen buffer). Computer programs use buffers to store data while they are running. If it were not for buffers, computers would run a lot less efficiently and we would be waiting around a lot more. |
| Buffer Overflow | A buffer overflow occurs when a program or process tries to store more data in a buffer (temporary data storage area) than it was intended to hold. Since buffers are created to contain a finite amount of data, the extra information - which has to go somewhere - can overflow into adjacent buffers, corrupting or overwriting the valid data held in them. |
| Buffer underrun | An error that can occur data is recorded onto CDs, when the data stream falls behind the laser that's burning the CD. Usually buffer underrun results from poor CD recording software, a slow computer, or a recordable-CD drive with insufficient buffer memory. |
| Buffer Zone | An area around a feature (i.e. the area around a point, a line, a poly-line or an area). |
| Buffered memory | Memory modules that have extra chips on them to support Error Checking and Correcting (ECC) functionality. |
| Burn | When you "burn a disc," you write data on it. If you were taking an SAT test, the analogy would look something like this: Hard Disk : Write :: CD/DVD : Burn The reason the term "burn" is used is because the CD-writer, or burner, literally burns the data onto a writable CD. The laser in a CD-writer can be cranked up to a more powerful level than an ordinary CD-ROM laser. This enables it to engrave thousands of 1's and 0's onto a CD. So that is why people talk about "burning" songs or files to CDs. They could just say they are "writing" the data to a CD, and it would make sense, but people seem to think "burning" sounds cooler. |
| Bus | The computer's primary bus is called the frontside bus and connects the CPU to the rest of the components on the motherboard. Expansion buses, such as PCI and AGP, allow data to move to and from expansion cards, including video cards and other I/O devices. While there are several buses inside a computer, the speed of the frontside bus is the most important, as it determines how fast data can move in and out of the processor. |
| Bus Topology | This network topology has computers connected to a strand of network cabling that is connected to network repeaters at one end and terminated at the other. If you break part of the cable or remove the terminator, all machines on that segment lose communication with the network. 10Base2 was a widely used bus topology network in its day. |
| Business to Consumer (B2C) | A form of doing business that deals with selling goods and services to the consumer marketplace. Examples of this would be selling consumer electronics, toys, or pet supplies. This contrasts with the business to business model. |
| Byte | In computing a byte is the basic unit of storage. A byte is a logical collection of 8 binary bits. A byte can therefore store a single integer value from 0 to 255. Collections of bytes can store larger number ranges or be used to represent other forms of data. Half a byte is a nibble, other common names given to collections of bytes are: Name Number of bytes nibble 2-1 0.5 byte 20 1 word 21 or 22 2 or 4 dword 22 4 kilobyte 210 1024 megabyte 220 1,048,576 gigabyte 230 1,073,741,824 terabyte 240 1,099,511,627,776 petabyte 250 1,125,899,906,842,624 exabyte 260 1,152,921,504,606,846,976 zettabyte 270 1,180,591,620,717,411,303,424 yottabyte 280 1,208,925,819,614,629,174,706,176 |
