“Get a Personal Trainer for Your Computer!”©

NOTE:  Items highlighted in RED are defined elsewhere in this Glossary, while items highlighted in BLUE are site links for further information.


DAC: Digital-to-audio converter.  Computers generally play rather poor audio, particularly music.  This device, which can plug into a USB port on a computer, reroutes the digital music on the computer before it reaches headphones, to provide a heightened listening experience.

demon (1)DAEMON: [Actually pronounced “deeemon”].  This is an unattended (i.e. not initiated by a human) computer program that runs continuously in the background until required (at predefined times or in maybe in response to certain events), when it then performs specified tasks.  Deamons monitor power grids, transfer money, traffic e-mail and generally help run our daily complex computer networks.  The most common daemon is the “mailer-daemon” that you receive when get when your e-mail is returned by a server, informing you that there has been a delivery failure.  The daemon has automatically bounced the e-mail, possibly because you misspelled the address or the recipient switched servers.  The term comes from Greek mythology, meaning “guardian spirit” in a protective sense and not the evil devil seen in horor movies.

daisy_chainDAISY CHAIN: Connecting one device to another of the same.  Sometimes this is acceptable (e.g. with hubs), sometimes not (e.g. surge protectors).

DALLAS: Microsoft’s information services business (coordinated with its Azure applications and other legacy applications) enabling developers to instantly find, purchase and manage datasets for the drafting of new cloud applications.

DARK DATA: Not the negative term you were probably expecting:  Actually, it’s neglected data, data logs and archives that are filed rather than destroyed, preserved for possible use someday, or maybe for compliance purposes.


DarknetDARKNET: A closed private network of computers, often used for file sharing of copyrighted music and other digital materials. 

DARKWEB: The part of the Internet and its services used for criminal activities.  See also Black Sites, Silk Road, Shodan. (Some define the dark web to also include archeological elements like broken links and dead satellites that have disappeared.) Not quite the same as the Deep Web, discussed below, although these terms are often used interchangeably. The Dark Web could be considered part of the Deep Web.

DARPADARPA: [Sometimes, just ARPA] See, Internet.  Stands for the Defense Advanced Research Projects Agency, the U.S. Department of Defense’s independent research branch.  Responsible for such military and commercial successes as GPS, the computer mouse, the Internet, ARPANET, Unix and parallel computing.  ARPA came into being in 1958 as a response to the success of Sputnik, Russia’s first manned satellite.  It changed its name to DARPA in 1971, then back to ARPA in 1993.  It then went back to DARPA in 1996. See also, Iarpa.

DART: See Google Dart.

DARWIN: The Unix part of Apple OS X, see Unix for more.

Dash ButtonsDASH (Amazon): A wand-like device used over a Wi-Fi network that can be used with the Amazon Prime service to order products with one click.  The idea is that you stick a button near products that you frequently replenish and then, when you’re about to run out of that item, you press and release the appropriate Dash button to automatically press an order through Amazon, over Wi-Fi, with the products shipped free through Amazon Prime.  The button is $4.99, credited back with your first order.  In the first year, Amazon has brought the number of Dash buttons up to 100, including Clorox, Doritos, Lysol, Maxwell House, Pete’s Coffee, Red Bull and the like, with many more to come.  Apparently, you need a button for each item, seems like a lot of buttons to me, but apparently it’s working for Amazon. Not available everywhere yet.

DASH: An graphic shortcut launcher includashded in Version 11 and later of Ubuntu Linux which provides users with a simple way of getting to shortcuts, applications and programs, by clicking on the Ubuntu logo in the upper left corner of the screen.

DASH7 (ISO 18000-7): An ultra-low power wireless data technology famous for its performance and reliability by NATO militaries and commercial customers.  It’s range of up to 1,000 meters, long battery life and ability to penetrate water and concrete make it preferable to the older ZigBee technology.

DASHBOARD: A data visualization tool like

that on a fighter jet’s HUD or a car’s front panel which displays the status and key performance indicators (“KPIs”) for specific software package(s) in one place.  Image at right is from ClaimCare, a company that creates custom dashboards for medical offices.

DATA: The stuff that’s either manually entered or imported into a computer that is then manipulated by a computer program.  Data can be items of information, such as text, numbers, statistics or other information. The singular of data is “datum,” a singular piece of information, like an integer (see numbers).

DATABASE: A structured collection of “records,” each containing specific “fields,” which are stored in a computer system for organization and retrieval.  Think of a database as a collection of recipes, each on a 3 x 5 card (the “record”) with the same type of information in the same place on each card (i.e. name, category (appetizer, main course, dessert), ingredients, cooking instructions, serving instructions, source; the “fields”).  You can search through all of the records according to the fields for each record (e.g. desserts, chocolate, from Aunt Margaret).  Databases can be either “flat” (consisting of one large table), “relational” (consisting of several interconnected tables, representing complex data relationships), network or hierarchical (a record structure linking records like a “family tree,” such that access to each record type starts at the top of the hierarchy and moves downward).  Popular relational database programs include Oracle, SQL Server, IBM’s DB2. A commonly used acronym when discussing databases is “CRUD,” which stands for “create, read, update and delete”.  Much code involves, for example, creating a database for a new customer, or updating its preferences, then saving the results or even deleting the customer at some point.  INTERESING NOTE: Did you know that you can also use fields in Microsoft Word:  Using the Insert tab or CTRL+F9, you can create, edit, format, calculate and toggle many types of fields within Word documents, essentially “placeholders” that store and display different types of data, speeding up the creation of documents.

DATA CENTER: A central location (either physical or virtual) for the storage, management and availability of data for a particular area of knowledge or a business.  For example, IBM may have its data center in Armonk, NY or the National Institutes of Health may be in Washington, D.C.  Centers can be managed through a variety of “systems” that maximize their efficiency, most common among them being ITIM (Information Technology Infrastructure Management), DCIM (Data Center Infrastructure Management), BMS (Building Management System), NMS (Network Management Systems), all quite complex and expensive.

DATA-CENTRIC: A buzz word for computers, networks or programs which focus on collecting, distributing and analyzing both structured and unstructured data.

DATA LAKE: A massively large data storage repository  with enormous data processing power.  Usually the data is raw, i.e. in native format, for use by anyone who wants to process it.  The term was coined by James Dixon, Chief Technology Officer of Pentsho, who wrote in his blog “If you think of a datamart as a store of bottled water - cleansed and packaged and structured for easy consumption - the data lake is a large body of water in a more natural state.  The contents of the data lake stream in from a source to fill the lake and various users of the lake can come to examine, dive in, or take samples”. See  also Server Farm, Big Data.


DATAMATION: A computer magazine read mainly by “suits” (i.e. business types), originally published in paper form between 1957 and 1968, now online ( devoted mainly to business matters.  Hackers, particularly, like to make fun of the magazine, which can be pretty stuffy.

DATA HOTELS: See, Server Farms, Server Lakes.

DATUM: See Data.

DAUGHTER BOARD: A printed circuit board (other than a modem, sound or video board - see riser board) that plugs into the number one slot on a mother (main) board, usually carrying the main processor and cache memory.

 dB, dBm:  dB is a standard measure of signal strength in decibels used for cable and telecommunications signals.  dBm is the power ratio (which can be translated to watts) of the radio power per one milliwatt.  The lower the number, the better the signal strength, because dBm is actually expressed as a negative measurement.  The term derives its name indirectly from Alexander Graham Bell and is a complicated logarithm.  Click HERE for more.

DBA: Database Administrator.

DBMS:  Database Management System.  Generally, a database is exactly what it sounds like; a collection of data, which is stored in records containing fields of information (much like a recipe card in a storage box).  It needs a program that is a DBMS that enables storage, modification and extraction of pertinent data from the database.  Requests for information from a database are generally made in the form of a queryThe set of rules for constructing queries is known as a query language.  Different DBMSs support different query languages, although SQL is most often used.  These languages are often called 4GLs, standing for Fourth Generation Languages.  Depending on the way that the data is organized within the program, databases can be relational, network, flat or hierarchical. (See, for example, RDBMS and DATABASE.)

DCIM:  (1)  Stands for Digital Camera IMages. This is a default folder for digital camera (even smartphone camera) images.  It is intended to keep images organized.  For example, if you insert a memory card into a digital camera, the camera immediately looks for the DCIM file to store images and, if none exists yet, it will create one. Same for many scanning and photo editing software programs, they look for the DCIM folder by default. (2)  It can also stand for Data Center Infrastructure Management, software which helps data center operators safely maximize the efficient use of power, cooling, and space capacities.

DCOM: Distributed Component Object Model (formerly Network OLE [Object Linking & Embedding]) is a Microsoft technology for defining the remote procedure calls (“RPCs”) that allow distributed objects to be run remotely over a network.  DCOM is Microsoft’s counterpart to CORBA (Common Object Request Broker Architecture) from other vendors.  This is hard to describe in English, but basically this is the software that allows the coordination of various software modules that are designed to work together but reside in multiple computer systems, so that a program in one machine sends a message to an object in a remote machine to perform some processing, and then the results are sent back to the calling machine.

DoS/DDoS: Denial of Service/Distributed Denial of Service attack.  A type of cyberattack (see Spyware) which floods web servers with e-mail or processing requests, making it unavailable to its legitimate intended users.  They often attack online businesses, causing massive loss of revenues and the resulting  collateral damage to their reputation.  They are also used by oppressive governments and political hacktivist groups, for extortion, by business competition and other more personal reasons, as DDoS attacks can shut down a server for lengthy periods until they are resolved.  DoS and DDoS are not exactly the same.  DoS attacks usually use only a single internet connection to either exploit a software vulnerability or flood a target with fake requests in order to exhaust server resources.  DDoS attacks, on the other hand, tend to be launched from multiple connected devices that are “distributed” (hence the name) across the Internet, such that these multi-device and multi-person attacks are much more difficult to deflect due to their sheer volume, and also because they tend to target the network infrastructure and not just a single server. DDoS attacks are, therefore, most often launched from botnets which infect large clusters of connected devices like cell phones, PCs and routers, by propagating malware infections that then allow the attackers remote control over those devices, while DoS attacks are more often launched by using readily available tools (like Low Orbit Ion Canon) or even home-brewed code.  Further, these attacks can be generally subdivided into Application Layer attacks (which overload the server with huge numbers of requests requiring resource-intensive handling and processing, like HTTP floods, slow attacks (e.g. Slowloris, Rudy) or DNS query floods, because only 50-100 RPS [Requests per Second] can cripple most mid-sized websites.  The second subcategory is Network Layer Attacks (almost always DDoS attacks, which operate on Layer 3 0r 4 of the OSI model, by clogging up the network pipelines via UDP flood, SYN flood, either NTP or DNS amplification and other high-traffic events which can shut down most web network infrastructures with no more than 40Gbps or packets-per-second (PPS). Both types of attacks, however, flood the server with ten times these limits, just to be certain.  For a specialized type of DoS attack, see fork bomb.

DEBUGGING:  The process of locating and fixing errors (“bugs”) in computer programs.  The term is said to have been coined, or at least popularized by Grace Hopper.

DEC logoDEC:  Digital Equipment Corporation.  A major player in the U.S. computer industry, a leading vendor of mini-computer systems (through its VAX and PDP products). Started in Maynard, MA in 1957, it was acquired in June 1998 by Compaq, which subsequently merged with HP and disappeared in May 2002, at which time some of DEC was also sold to Intel.

DECIBELS:  See Db, above.

DECISION TREE:  See flowchart.

DECOMMISSION:  To withdraw from service, as in decommissioning a computer from a network, or decommissioning a network (e.g. after a merger).

Decoy appsDECOY APPS:  A/K/A ghost apps, secret, safe or vault apps.  Smartphone apps and their shortcuts that are disguised as innocent-looking icons (like the example posted by McAfee at the left), like calculators or music players, which are actually links to photos, videos, texts or other content that the user desires to hide.  Often used by kids to hide their online activity and communications from their parents, adults use them to hide information, password lists, legal documents or even spousal cheating, as most decoy apps are password protected.  There are literally hundreds of Android and Apple apps for this purpose, just type “decoy app” into any web browser and you’ll see apps like Secret Box, Private Photo Vault and Album Lock.  Some (e.g. Secret Calculator) proudly disguise themselves as working apps (like a calculator) to hide what’s behind it.  These are not to be confused with “disappearing” apps like Snapchat, also often used by teens, with which the photo or text, once viewed, disappears within seconds.  Decoy apps are much more dangerous because the content is not erased and can be hacked or transferred.  There are also apps tht allow teenagers to anonymously share their deepest anxieties and other feelings without adults being able to look in.  The After School App, designed to be accessible only to teenagers as a safe place to discuss sensitive issues like bullying without having to reveal their names, in 2015 it expanded to more than 22,300 high school campuses, with etween 2 and 10 million users in the U.S. alone.

DEDUPLICATION:  A/K/A “dedupe”.  The process of removing identical or similar records which appear in a database, such as a mailing list.

[THE] DEEP WEB (a/k/a Invisible Web):  The concept that most search engine results, partly because they capture static (fixed and therefore don’t change very often) and not dynamic (are constantly changing) pages, only scratch about one percent of the surface of the billions of web pages on the Internet. Some estimates are that Google, Bing and Yahoo (the so-called “Surface Web”) combined, only access about 5% of what’s on the whole  Internet. There is an oft-quoted statement by Mike Bergman, founder of BrightPlanet, comparing searching on the Internet today to dragging a fishing net across the surface of the ocean, where a great deal may be caught in the net, but there’s still a wealth of information that is deep and therefore unfound.  After the surface net captures its results, the rest of the sites are deeper and not nearly as easily available.  This is because those sites are behind private networks with their own databases (even many public sites like NASA or EDGAR), on intranets, government sites, protected sites or on stand alone pages.  It is also often used as a vehicle to locate and join red rooms, (a/k/a Bloody Rooms, Virtual Harassment Terminals), which require login membership payable via Bitcoin, which then allow the members to view live video streaming of hidden sites with the option of live IRC chats for the purpose of heinous acts and blatant torture by evil individuals.  An example would be a hidden site where someone is tied to a chair in a dungeon and the members would type what they want done to him or her (“set fire to her hair,” “punch him in the stomach,” even “kill him,” etc.).  They’re the old “snuff films” updated to the digital era. They can’t be located via a traditional web browser, usually they can be found with a specific URL or address.  Some say this is just the stuff of urban legends or scams to extract money from gullible netizens, others say they’ve actually seen them, even though they’re in the minority.

Recently (2014-5) DARPA has developed the Memex Deep Web Search Engine with the goal of building a better map of all web content, including the Deep Web, and uncovering patterns in online data that could help law enforcement and others. Memex is initially being used to track human traffickers and will expand to include counter-terrorism, as well as locating missing persons, response to pandemics, and for disaster relief as it evolves. What’s the difference between commercial search engines and Memex?  Commercial search engines produce results based on popularity and ranking, while Memex searches content typically ignored by them, including unstructured data, unlinked content, temporary pages that are quickly removed before ranking, chat forums and the like.  And the traditional web “crawlers” can’t find dynamic unlinked content, private websites, contextual web, scripted and non-HTML/text content and limited access content, where much of the Deep Web is located.  Memex (through the TOR anonymizing browser) also automates the crawling of hidden services page where criminals conduct business under the radar of law enforcement (i.e. the Dark Web, discussed above) and creates “data maps” of the relationships between different items of data.  None of this browsing is considered hacking, as it searches only public content and not content that is protected.  The Deep Web isn’t the same thing as the Dark Web, discussed above, although the Dark Web could be hidden within the Deep Web.  There are other browsers to search the Deep Web:  DeepPeep, Intute, Deep Web Technologies and Scirus are just a few of the search engines available.  Most suggested first stop is The Hidden Wiki.  Click HERE for more.  Click HERE for a list of dark web sites.

Defcon logoDEFCON:  A DEFense CONference, usually held in Las Vegas each year at the end of July or beginning of August, started in 1992 by the Dark Tangent, which is the world’s longest and largest underground hacking conference.  The founder of this conference, Jeff Moss, also started the Black Hat convention, much more expensive to attend.  Both are the most famous computer security conferences in the world, where hackers meet to discuss ways to protect criminals from penetrating businesses, governments, power grids, air traffic controls, etc.  It is said that the term DEFCON is actually taken from the movie War Games, referencing the 5-level U.S. Armed Forces Defense Readiness Condition.  In the movie, Las Vegas was selected as a nuclear target and, since the first conference was held there, it was adopted.

DEFAULT: While, in some circles, the term default connotes bad things (e.g. “You’re in default on your mortgage payments” - meaning failure, inaction or neglect on your part), in computers it’s a completely different and benign thing. It refers to a predesigned setting that is used by a computer or program when nothing more specific is supplied.  For example, the default printer is the one that the computer assumes is the standard printer for programs on that computer.  The default settings for Windows are those standard settings created upon installation, unless specifically modified. Often synonymous with the term “factory settings”. When modifications to the default are removed, the settings immediately revert back to the default or factory settings.

DEFENSE IN DEPTH:  The use of multi-layered security countermeasures to protect computers from intrusions and viruses, particularly in enterprises.  The same process used in military countermeasures, a strategy based on the principle that it is far more difficult for an enemy to defeat a complex defense system as opposed to a single barrier.  So, for example, a computer security defense might include anti-virus software, anti-malware/spyware software, a hardware and software firewall, multi-level password verification, possibly biometric authorization, electronic countermeasures, physical security measures, personnel training and policies - some or all of these measures in various layers.  Similar to the use of a “spam cocktail” (the use of several different technologies, sometimes in layers) to increase the accuracy of anti-spam software and reduce the number of false positives.

DEFRAG:  Means defragmentation. Regardless of how Windows portrays your folders and files (My Computer, Windows Explorer), your computer files are actually always “fragmented” (exploded into small segments throughout the disk) when stored on the hard drive.  Consequently, the storage “blocks” on the drive must be periodically rearranged by defragmentation so that they are compressed into fewer, more easily accessible, fragments which are at least more contiguous to each other.   The files are sent to the outside of the disk, based on their size and frequency of use, beginning with the Master Boot Sector, leaving more space on the interior of the disk.  The computer can then store more data on the drive more efficiently, which reduces access time to display files. [Don’t use on SSDs, though - they can shorten their life.]  For more, see FAQ #8.

Remember that brain teaser puzzle where the goal is to get the two ball bearings into opposite ends of a plastic holder shaped like an orange wedge?  The solution is to spin the entire holder in order to get the two metal balls on opposite sides using centrifugal force?  If you had lots of balls (parts of files) the process would be much the same as defragmentation. (Thanks to Aha! ALL UPHILL Puzzle for the photo)

DEGAUSSING:  The process of attempting to eliminate a remnant magnetic field, such as those surrounding CRT monitors (see Screens) and magnetic disk drives.  It is  named after the Gauss unit of magnetism, named after Carl Friederich Gauss.  It is theoretically impossible to reduce the field to zero due to a principle known as magnetic hysteresis, so degaussing typically induces a only smaller field known as a “bias”.  It was invented during WWII when it was used to reduce the magnetic signatures of warships so that they were not detected by German magnetic mines. 

DELVE:  (Original codename “OSLO”):  A service from Microsoft for its MS Office 365 customers, which displays relevant information and connections from across a user’s work life based on the relevancy of the work they are doing on the computer at the time.  The platform, powered by Microsoft Office Graph, learns how a user and their business colleagues communicate, collaborate and share files and the work that is done with that information.  It helps you locate files and information and intuitively suggests other content that might be useful and relevant, to make the job easier. 

Dell logoDELL:  One of the largest U.S. computer manufacturers and information technology corporations.  Named after its founder, Michael Dell, who started the company back in 1984 while a student at the University of Texas.  The slanted “E” was supposed to symbolize Michael Dell’s desire to “turn the world on its ear”.  Dell went private in 2013.

DEMARC:  Sometimes called MPOE (Minimum Point Of Entry).  In telephony, the demarcation point is the point at which the telephone company network (Public Switched Telephone Network, i.e. PSTN) ends and connects to the cabling at the customer’s premises.  This is also known as the “loop” or “local loop” which is the wired connection from the telco’s central office to the premises.  This is defined by FCC Rules 47 CFR Part 68.  The actual demarc point is the network interface device (“NID”)/ channel service unit (“CSU”) connection:  The NID is the telco’s property; the CSU is the customer’s.  Usually the residential NID is at a grey plastic waterproof junction box on the outside of the home which contains a lightning arrestor, fuse and test circuitry for the telco’s remote testing of the connection.  Also, there is often a test jack which is usually connected to a loop of wire, to be used to isolate and troubleshoot faults in the premises wiring.   Commercially, the NID is usually a 66 or 110 Block, the left side of which is the incoming cable from the telco, the right side of which is customer premises wiring. See, 66 Block.  [Don’t confuse this with DMARC, below.]


demarc diagram small



DEP:  A Windows technology security feature in Windows Vista and Internet Explorer 8 which is intended to prohibit hackers from writing code into pagefiles and swapfiles by inserting a special bit into the disk version of an address, making it non-executable.  If DEP senses a problem, it may prevent you from opening a specific program (you would then have to deactivate DEP).

DEPENDENCY CHAIN:  a/k/a software coupling.  The actions of a program or module are dependent on other modules or programs in the system.  The programs, components, processes and services in the computer’s operating system and registry are interdependent, such that changes in one affect the other.

DEPLOY:  Fancy corporate enterprise speak for “install,” as in setting up multiple computers with a standard system image across an entire organization, possibly using Windows DISM, discussed below.

DES a/k/a Digital Encryption Standard:  A cryptographic method developed by IBM in the 1970s (and continually improved over the years) which is used on millions of devices, mostly cell phones every day.  See encryption.

DESIGN THINKING:  A design philosophy first proposed by David Kelly and his company Ideo which combines design with empathy for product users.  Ideo designed many of the Apple products and things like the thumbs up and thumbs down button on the TiVo remote.

desktopDESKTOP:  (1) A designation for a computer that sits on a desk and is generally a full system (i.e. CPU, keyboard, monitor and mouse) as opposed to a mobil system. (2) The initial display that appears on a computer’s monitor when Win 8 Desktopa computer is booted.  It usually includes the background (“wallpaper”), icons for files, shortcuts and programs, a task bar with a menu at the bottom (in Mac, the menu bar is at the top), and various other optional items.  The desktop can be customized to a user’s preferences, so that it emulates a traditional (furniture) desk top, having all of the frequently used items available at a click (“shortcut”) rather than searching for them through menus and sub-menus. (WinXP shown top left, Win8 at right)

DEVICE:  As used in this Glossary, an item of hardware (such as a computer, printer, TV, phone or the like), or sometimes a subassembly of that hardware (modem, card or board), as opposed to the software or instructions that control that particular hardware.

DEVODEVO:  Yes, it was the name of a rock group from 1972.  But its name cane from the word “de-evolution,” the idea that humans are regressing into a destructive herd mentality.  Although networked cell phones and social networking came along later, they considered all of this part of de-evolution.

DEVOPS: A mashup of the terms “developer” and “operations,” describing how the previously distinct entities have began to overlap.

DHCP: Short for “Dynamic Host Configuration Protocol”. Your computer has devices like broadband modems that may have a different IP address every time you connect to the Internet network, even more often.  DHCP keeps track of these changes and automatically keeps you connected to the Internet even if the IP address changes.  DHCP servers are assigned a range of IP addresses and assigns an unused address from this range each time a host signs on.

Telephone symbolDIAL-UP:  Where a computer connects over a telephone line using a telephone modem.  As opposed to cable or DSL (click HERE), it is not “always on” but only when connected over the phone line.  Also, it’s slow, not broadband.

Digg LogoDIGG: Started as an experiment in 2004 by Internet entrepreneur Kevin Rose, it was one of the first sites to promote the idea of people voting stories up or down in order to determine their “viewability rating”.  The name came from the ability to “dig(g)” a linked site, hence the use of a shovel icon at times.  The site has gone through a number of revisions and is still quite popular.  But Revision 4 (2010) resulted in the site being unavailable for quite some time and caused defections, to sites like Reddit.  The so-called “Digg effect” results when the posting results in a sudden increase in traffic to the “dugg” website, sometimes referred to being “Dugged to death”.

DIGERATI:  The digital version of literati, a reference to a group of people expected to be knowledgeable about all thing digital.

DIGITAL: This describes electronic technology that generates, stores and processes data in terms of two states: positive and non-positive.  Positive is represented by the number 1, non-positive by 0.  Thus, digital data is expressed by a string of O’s and 1’s.  Each of these digits is a bit.  For more discussion, see Bits and Bytes.  The predecessor to digital technology was analog.

DIGITAL ASSISTANT:  Software like Apple’s Siri, Amazon’s Alexa (Echo), Google Now, Google Assistant and Microsoft’s Cordana that use voice recognition to let humans communicate with machines to perform tasks.  Every generation gets better and better.  Next step appears to be the use of AI to increase the ability of DAs.  Viv Labs, the creators of Siri before Apple purchased it, are working on a product named ViV which will be “what might have evolved if Apple hadn’t purchased it”.  It will have noun recognition and be available for embedding into devices other than cell phones like the IoT coffee makers that you can tell your digital assistant to make your coffe or TVs and for other services, like restaurants and car services.  Meanwhile, the big guns, Google (which purchased AI company DeepMind, and has brought AI expert Geoffrey Hinton and futurist Ray Kurzweil as consultants) to develop the Google Brain evolution from Google Now, as well as Microsoft and Apple are moving forward on their own. 

DIGITAL BOOK:  See, e-book.

DIGITAL CERTIFICATE: A sort of electronic credit card” that establishes your credentials when transacting business on the Web.  It is issued by a Certification Authority and contains your name, a serial number, expiration date and a copy of your public key (see PKI), so that the recipient can verify that your certificate is real. 

DIGITAL CLOTHING:  Something new in ID photos, where software is used to superimpose suits or uniforms on photos taken for corporate or driver’s IDs.

DIGITAL FOOTPRINT:  A phrase encompassing all of those digital indicators of modern people, including e-mails, texts, geotags, credit card receipts, cell phone records, web searches, Facebook and Twitter transmissions and the like, all of which can be put together to make a digital composite of a person.

DIGITAL FORENSICS: The application of scientific tests related to crime detection, through the extraction, analysis and documentation for recovering data from physical media, such as PCs, servers, cellular phones and IoT devices.  Mostly used by enterprises and law enforcement agencies for criminal investigations and civil litigation, the process involves both hardware and software tools. Hardware tools can include things like forensic bridges (a/k/a write blockers) which connect to and safely extract data from storage media; forensic recovery of evidence devices (FRED) workstations that plug directly into networks to analyze data; SHADOW, a speedy device that can image a suspect’s hard drive at the scene of a crime; media duplication terminals that can capture data from CDs, DVDs, USB and flash drives and mobile devices, and capture screens; and portable evidence scanners that can grab screen captures and record video in the field.  Software can include such tools as Sleuth Kit, an open source suite of apps that can locate hidden files, recover lost documents and analyze registry changes on all common O/Ss; Wireshark, an open source packet sniffer;  CAINE, a Linux distro tailored for digital forensics which offers an integrated set of memory, mobile and network tools; Registry Recon, which can analyze and rebuild the Windows registry; COFEE, a Microsoft data extraction and documentation tool used by law enforcement, and Volatility, a memory forensics tool that can extract information stored on RAM.  All this, just to name a few....

DIGITAL SIGNATURE: An electronic signature that can be used to authenticate the unique identity of the sender of a message or signer of a document, providing nonrepudiation security.  Digital signatures are unique, can be time-stamped and cannot be imitated.  You need PKI to do this.

DIGITAL TRANSFORMATION (“DX”):  A term that has been around since the 1990s, which means the application of digital technologies to all aspects of business and society in general.  Think:  Cloud computing, IoT, mobile apps, etc.


DIGITAL WAVE:  See, Snapchat, Poke.  A very short text message.

DIJKSTRA ALGORITHM:  One of the first anDijkstrad most famous algorithm created, by Dutch computer scientist Edsger Dijkstra (1930-2002), which finds the shortest path in a group of elements collectively known as a graph.  Like a graph of zip codes, maps, sports teams, etc.

DIN CONNECTOR: DIN is short for Deutsches Institut fur Normung dV, the standards setting organization for Germany.  In many of the earlier PCs, DIN connectors were used for cable attachments.  See, e.g. photos of the keyboard DIN connector HERE.  DIN connectors also defined Centronics and RS-232 (DB-25) connectors. See the same link for photos.

diode symbolDIODES:  An electrical component on PCBs and semicodiode2nductors that allows electricity to flow in one direction only, blocking flow in the opposite direction. This is for the protection of the device, so that it does not become damaged by electrical surge. Diodes are usually made of silicon, but can be made of other materials.  They are like “valves,” which block electricity from traveling in the wrong direction.  They generally don’t operate until a “threshold point” of .6 voltdiode 3s is reached.  Each cathode has a anode (+)  and cathode (-) wire and is encased in a glass cylinder which has a dark band marking the cathode terminal.  The symbol is shown above.

DIP SWITCH: A type of small on-off switch (usually a “slider”) used on computer circuit boards and hardware to adjust settings.  Often used in place of a jumper.

DIRECT  ACCESS: A Windows 7 technology that lets employees remotely access corporate networks without using a VPN. Instead of establishing a connection and logging in to access corporate resources, things like file shares, intranet websites and network applications are made available to authorized DirectAccess clients.  However, establishing and maintaining DirectAccess on the administrative side is fairly complex, requiring such procedures as tunneling and security certificates, making this feature more suitable for larger organizations.

DIRECTORY:  A part of the file system which contains files and is sometimes referred to as a folder.  The computer operating system  organizes these folders into a hierarchical structure often referred to as an “inverted tree”.  The topmost directory in any file is known as the “root” directory. See, taxonomy.  In DOS and Directory_TreeWindows, the root directory is begins with a backslash (“\”), in Linux it’s actually called “root”.  The directory below another directory is called the “subdirectory.”  And a directory above another directory is known as the “parent directory.”  In Unix and Linux, the directory you log in to is known as the home directory.  The directory you are currently working in is the working directory.  To directly access a file in a directory, you must use an operating system command.  Indirectly, it can be accessed through the appropriate program.  If you are using a command line, you must specify the entire path to the file, listing the names of all of the directories above the file with a backslash in between each.  [e.g.:  “C:\Users\Joe\Program Files\Office 12\Word\resume.wpd”]  Path names can be either absolute (the full path from the root directory, e.g. “/home/joe/work”) or relative (the path from your working directory, e.g. “joe/work”).  See also, taxonomy, jump list.

DIRT:  Electrical power anomalies.  Dirt in an electrical power system is a pollution of the wave system, depriving the system of clean, constant power.  Dirt can be caused by such events as power surges (a short but powerful event like a lightning strike), transients (a more continuous or periodic event like inductive kickback from a motor switching on or electro-static discharge) as well as total harmonic distortion (THD).  Dirt can have a significant negative effect on not only through poor electric quality but also the behavior of electrical equipment like motors, reducing their loads and lifetime, even causing incorrect behavior. See noise for cell phone interference.

DIRTBOX (DRT BOX):  Another word for a “cell site simulator”.  It;’s a phone device which mimics a cell phone tower.  It’s designed to create a signal sufficiently strong that it forces dormant mobile phones to automatically switch over to it. It’s like the FBI’s Stingray, but more powerful.   It’s not legal for personal use, as it is a combination of a cell phone jammer and detection device which is used by law enforcement to locate cell phones and collect information from them, by mounting the box on aircraft and autos to foil criminals which use thieir cell phones to communicate.  The name is derived from the original developer, Digital Receiver Technology, Inc. (“DRT”).

DISABLED:  Hardware that is found on a computer, but not connected.  The opposite of enabled.  Check the computer’s device manager for such devices.

DISCO:  Not a throwback to the ‘80s, a .disco file is a Web Service Directory file which opened by an SQL database app and InfoPath (an app included in the premium versions of MS Office).

DISINTERMEDIATION: Actually more of an economic term, it means to “remove the middle man”.  For example, selling products on the Internet directly to consumers may eliminate brick-and-mortar storefronts; selling downloadable applications for cell phones may eliminate carrier distinctions.

D2C: Stands for “Disk to Cloud” which refers to storing data from a computer or network to the public cloud for security.  Similarly, D2D2C refers to “Disk to Disk to Cloud” which is storage to a private cloud, which allows more corporate control and hence more security for sensitive data.

DISK:  See, hard drive.

DISK CLEANUP:  Starting with Windows Vista, a Windows feature to remove unnecessary hard drive filesThis includes duplicate Windows DLL files.  It does this through a technology called “componentization” which creates a “WinSxS” (Windows Side-By-Side) file, which can be cleaned up with this utility (Windows Update Cleanup feature). See also, hard drive, DLL hell,

DISM: WindowsDeployment Image Servicing and Management tool.  It is generally used by IT departments and OEMs to create, manage and install identical systems on multiple PCs.  But it can be used for repairs to Windows, and recovery as well.  It is a command line tool with over 100 powerful functions.  Starting with Windows 10, it is bundled with the custom recovery image process.  Definitely not for beginners.  But for advanced users, it can even solve O/S corruption issues with a line like “dism.exe/Online/Cleanup-image /RestoreHealth”.  Or roll back from a bad Windows upgrade.  To learn more, click HERE.

DISPLAY FORMAT:  Refers to the overall width vs. height format (also sometimes called the “aspect ratio”) of a video display.  While it started as 4:3, presently standard formats are usually either 3:2 or 16:9.

Aspect Ratio 32 Aspect ratio 169

See also, letterboxing.

display port logoDISPLAY PORT: A port and cable developed by VESA (see Associations) primarily for connecting a video source (but also sometimes an audio source) to a display device such as a computer monitor (see Screens).  See Connectors for photos.  It was developed as a royalty-free alternative which would replace VGA, DVI, HDMI and FPD-Link, or at least be compatible with the use of adapters.  It was advantageous because it was the first display interface to rely on packetized data transmission, much like ethernet transmissions, making it faster with less pins to achieve a higher resolution.    It has been revised through Ver. 1.4 (2016) and is now a common connection on many PCs, now that VGA is being phased out. Also: mini/micro-display port.  There are available dongles that can convert VGA and HDMI to display port for older monitors.  Below, a example of a display port connector and a common videDisplay port on cardo card layout for many desktop video cards (note absence of VGA, and presence of HDMI to easily connect to TVs).  Click HERE for more about video connectors.

display port connector

DISRUPTIVE TECHNOLOGY: A term applied to entities which disrupt the prevailing business model.  From a book by Clayton Christensen (“The Innovator’s Dilemma”), which posits that people disrupt the status quo when they come up with a less costly product or version of a product, making it available to more consumers, providing growth..

DISTRIBUTED DATA: A database where the data is not all stored on the same storage device or CPU, but is instead stored on multiple computers either in the same physical location or even over a network of interconnected computers in various physical locations.  Opposite: Centralized, all on one computer.

DISTRIBUTED MODEL/DISTRIBUTED NETWORK MODEL - “DISTRIBUTED COMPUTING”: A computer network in which the individual server computers act relatively independently, although they may still be connected to a central server, so that individual users experience a uniform experience when it comes to performance and applications, even though they may not be on their individual computer.  See also, cluster, parallel, grid and cloud computing.  Similarly, as relates to a business organization, one in which individual branches act relatively independent of each other and the head office.  Relatively independent means that they may all share inventory, communicate with each other, and leave the accounting , billing and purchasing functions to the head office. 

DISTRIBUTED WORKFORCE: A term coined by Silicon Valley venture capitalists for odd jobs hosted by sites (like TaskRabbit or Postmates) which auction people to perform tedious or time-consuming chores, like car washing, courier services, or picking up dry cleaning or prescriptions.

DISTRO:  Short for “Distribution.”  This term is mainly used in Linux, and it refers to a version of Linux made by a specific distributor (e.g. Red Hat, Ubantu, etc.).  In Linux, all distributions use the Linux kernel, but everything else is different for each distribution, making each unique to a limited extent.  So a Distro is a compilation of software and then some additions which make the software unique.  Somewhat like the way Windows software can be slightly different for business, home, pro, etc.  A comprehensive list of distros and their attributes can be found at Wikipedia, click HERE for the link.

DKIM: An internet authentication system (successor to DomainKeys, below), that mitigates the risk of trusting e-mails by insuring that they originate from where they appear to come from.  Originated at Yahoo in 2007, who was at that time a  major e-mail provider. It works like this:  The owner of a domain generates an encryption key pair, putting the public key in a special TXT record within its forward lookup zone at its public DNS server, while the private key is stored on the mail server, which signs every outgoing message with that private key, adding it to the e-mail header along with other information.  When the receiving mail server sees an inbound message from a domain, it then checks that domain’s public DNS zone and retrieves the public key for that domain, which it then authenticates with the private key which was signed with the outgoing message and, if it matches, determines that the message is authentic.  If not, recipients should be highly suspicious and regard it as spam, phishing or the like.  For some reason, although it is quite useful, it never made its way into Microsoft Exchange.

DLL: Dynamic Link Library file.  This is a very important file that is created in Windows upon the installation of every program, which “links” that program to a “library” of instructions about the operating system.  The file itself contains a library of procedures for that program (or sometimes a group of programs), essentially linking the execute file for that program with the rest of Windows, such as the printers or monitors, through mini-programs that can be called upon if and when needed. If the dll file is  missing or damaged, you get a “dll error” from Windows and your program will simply not open.

DLL HELL: A term referring to a situation where different versions of the same program are installed on the same computer, creating updated versions of the DLL files with the same name as other files already on the system, causing confusion.  Starting with Windows Vista, a file named WinSxS has remedied the problem where those updated DLLs often broke programs that still required the older ones, because the Disk Cleanup feature (Windows Update sub-feature) in Windows will remove the older versions of the DLLs for current programs. 

DLNA: Digital Living Network Alliance.  An organization established in September, 2005 that certifies wired and wireless digital products such as personal computers, consumer electronics and mobile devices toward the end of enabling a seamless environment for sharing those devices and their content.  The DLNA Certified logo ensures that a device has been tested and proven to be interoperable among various other devices that have been designed according to the DLNA interoperability guidelines.

DLP: Data Loss (or Leak) Protection. Used mostly in larger organizations, DLP involves scanning outgoing data such as web traffic (including web mail), IM, FTP and any other mode that sends electronic data out of an organization to prevent leakage of important corporate data or intrusion through unauthorized ports.

DMA: Direct Memory Access. This is a capability provided by some computer boards that allows data to be sent directly from an attached device (such as a  drive) to the memory on the computer’s motherboard, freeing the processor from involvement, thus speeding up the computer’s operation.  The alternative to DMA is PIO (“Programmed Input/Output”) in which all data transmitted between the devices goes through the processor.  A newer protocol is Ultra DMA, now on many SATA/IDE hard drives, which provide a “burst” data transfer up to 33  megabytes per second

DMAIL:  [LINK] A Google Chrome web browser extension which allows a sender of email to revoke a message at any time, and soon prevent recipients from forwarding your message as well. It was originally created by YouTube founders Chad Hurley and Steve Chen as Delicious, then sold to dMail and is free and will also be fremium.

DMARC: Domain-based Message Authentication, Reporting and ConformanceServer software protection built to reduce e-mail abuse such as phishing (see Spyware).  It standardizes how e-mail receivers perform e-mail authentication using the existing SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) mechanisms.  It’s supported by e-mail providers such as Google, Yahoo and Microsoft and protects over sixty percent of e-mail boxes worldwide.  Do NOT confuse this with DEMARC telephone hardware, discussed above.

DMI: Short for Desktop Management Interface, an API that allows software to collect information about a computer environment (hardware and software components).  This automates system management and is particularly beneficial in enterprise environments where many computers are being managed.

DNIS:  Dialed Number Identification Service.  Identifies a telephone caller.

DNS: Domain Name System (or, sometimes, Service or Server).  As discussed in URL, the Internet is based on numeric IP addresses, which are usually also English domain names.  DNS is the internet service that translates domain names into IP addresses, e.g... from “” to “” and vice versa.  See Public vs. Private and ICANN for more on this.  [ADVANCED INFO: For those who are involved in web hosting, there are several types of DNS records, among them:  “A” (“address” - points a domain or subdomain to an IP address); CNAME (“canonical name” - points to another domain or subdomain); MX (“Mail Exchanger” - directs to a mail server); TXT (“test” entry); AAAA (points to an IPv6 address); SRV (“service” points to a specific port such as VoiP or IM at a domain); and PTR (reverse of an “A” record, it maps an IP address to a hostname).]

DNS FILTERING: A type of web filtering for those subscribers who don’t have ISPs which don’t offer web filtering.  Instead, you can block suspect sites by switching your DNS server settings to go through a specific third-party DNS provider which can provide such security services (e.g. OpenDNS).

DNS REBINDING:  An Internet intrusion by which hackers use extra IP addresses for legitimate web sites in order to obtain access to routers and then computers which do not have adequate password and firmware protection.  It is not browser specific, and only applies to some routers.  See Security.

DNS ROOT ZONE:  The top level DNS zone in the heirarchy. That is, the DNS managed by ICANN.

DNSSEC:  Domain Name System Security Extensions.  A critical component of the Web architecture that matches site names to server locations.

DNS SINKHOLE:  A method used by security researchers to monitor Botnets and to block communication between an infected computer and its Command & Control server, preventing virus infections.  

DomainKey:  See, DKIM.

Do Not Track (“DNT”):  An option on some web browsers like Firefox that make it so that users’ browsing habits are not tracked, by not allowing cookies to be placed on their computer.  For more see this LINK.

DOCK: On Apple OS X computers and some PCs (HPs and the like), it is a user-modifiable row of icons that appears on the desktop with program shortcuts for easy selection.  Not to be confused with a docking station, which is a piece of hardware into which a laptop or notebook computer is placed, so that it more closely resembles a desktop computer, containing ports for printers, serial devices and the like.  Some docking stations are known as port replicators because they expand the number of ports and/or drives that the notebook can use but, unlike a docking station, they do not include an expansion slot. Some docking stations like Samsung’s Central Station are completely wireless.

DockerDOCKER:  An open source project for developers run on Linux, originally written by Solomon Hykes and released in 2013.  It deploys apps inside software “containers,” providing a degree of isolation from the O/S and other apps, providing more security and flexibility.

DOCSIS:  Cable modems use Data Over Cable Service Interface Specification  technology, including authentication and packet filtering, and providing built-in hardware firewalls, so that their networks are secure.

DogeDOGE:  Pronounced “dawg”.  A slang term for “dog” that is primarily associated with photos of the Shiba Inus breed (nickname “Shibe”) which are often Photoshopped to change the dog’s expression as well as to add single (e.g. “wow”) or two-word monologs (e.g. “true dat,” “so hip”), almost always in Comic Sans typeface.  This meme originated on 2/23/10, when a Japanese kindergarten teaches, Atsuko Sato, posted several photos of her rescue-adopted Shiba Inu dog.  After posting, doge’s fame grew after posting on The Verge and Reddit, and has been copied for various purposes.  Eventually, even a virtual currency named dogecoin was created (see Bitcoins).

DOMAIN: A domain name is an easy-to-remember shortcut or handle for a numeric internet address. A Top Level Domain (“TLD”) would be either Generic or Country Code.  For example:  The fictitious internet address would mean that the entire name is the top-level domain, is the second-level domain, and technet is a subdomain name.  Domain names, as regulated by Icann, have been limited to 37 characters (26 Latin characters, 10 digits and a hyphen).  At the moment, there are 22 generic top level domain extensions (see below), plus the 250 country codes like .up and .us.  Beginning in 2010, however, Icann will begin permitting domain names in non-Latin alphabets (e.g. Farsi, Hebrew, Chinese) in an effort to “internationalize” the Internet. And, in June 2011, ICANN approved an increase in the number of generic top level domains (“gTLDs”) from the current 22 (.net, .com and .org most common), adding new ones such as .cars, .sports, .museums, and the like.  Some proposed extensions are geographic (.paris, .boston), others tied to professions (.attorney, .cpa, .plumbing), still others, .music, and .news. The total could well cross 1,450 or more.  It remains to see how successful they will be, as people learn to migrate from .com and have to remember a variety of extensions.





















For a list of the country-code and other top level domains, click HERE.

DONGLE:  A term which started out as a reference to any very short cable used to connect hardware (like an external drive or USB ethernet or modem device) to a computer and which now universally refers to any small module with or without an attached cable (even a dongleUSB drive) which plugs into the external ports of a computer.  Sometimes, the dongle acts as a “security key” in the form of an intermediary plug or connector which is situated between the keyboard, serial or printer port and the hardware it seeks to secure.  The derivation of the term is somewhat uncertain, although most agree that it derives its name from the portmanteaux of “dong” and “dangle” because it usually “hangs off a computer”.  Gross, but accurate.

Jack Dorsey photoDORSEY, JACK:  Inventor of Twitter and, after that, Square.  Also at one time he said that he had aspirations to become mayor of New York.  See those topics for more.

DOS and DDOS:  Denial of Service and Distributed Denial of Service attacks. A DOS is an attack by a single computer (IP address) on a target web domain computer by inundating it with a tremendous number of packets, thereby overwhelming it and effectively shutting it down (i.e. “denying service”), making it too busy to respond to legitimate web traffic.  A DDOS is a geometrically more serious attack, because it is caused by a multitude of compromised computers (a “botnet” of hundreds, thousands or more unsecured and probably unaware “zombie” computers) which flood the targeted system in waves from many different IP addresses, not only continually incapacitating the target but also making it virtually impossible to filter out the “garbage” IP connection requests.  Of course, both the botnet and the targeted system are victims of this type of Trojan (see Spyware), which cannot be resolved as can a DOS, by finding and blocking the single IP address of the attacker.  A few facts:  Since 2003, DDoS attacks have been growing in intensity worldwide.  In 2003, the size of the largest attack for each year has gone from 1Gbps to 325 Gbps in 2014 (when there were over 133 DDoS attacks over 100 Gbps).  While most DDoS attacks last less than one hour, the largest attack in 2014 lasted 4 hours and 23 minutes. 40% of the attacks have been proven to be motivated by political or ideological disputes. On October 21, 2016,  hackers used a DDOS attack against Dyn (one of the largest Internet management companies in the country, located in New Hampshire), shutting down sites like Twitter, Spotify, Etsy, Netflix and GitHub for an entire day, effectively “taking down the Internet”.  See also, SMURF ATTACK, Spyware. Don’t confuse this with the DOS operating system (See below).

DOS:  See, Operating System. Disk Operating System, software purchased by Bill Gates from a Seattle hacker for $50,000, later pioneered by Microsoft, which became the basis for most PCs today. Developed by Microsoft in 1980 for IBM (PC-DOS), Gates retained the right to market DOS separately from the IBM PC, as MS-DOS, the precursor to MS Windows.  Also circa 1977, Radio Shack used its version of DOS named TRS-DOS in its TRS-80 computers.  For a listing of common DOS commands, click HEREThe interesting history:  Had Gary Kildall not screwed up, the story is told, he might have been Bill Gates.  Here’s why:  On August 21, 1980 bill gates photoIBM visited Gates at Microsoft and laid out their plans to build PCs.  Gates told them that he couldn’t supply an operating system, but referred them to Gary Kildall of Digital Research Inc. which already had an O/S called CP/M.  The next day,  IBM met with Dorothy McEwen, Kildall’s wife and DR’s business manager at DR’s Pacific Grove, CA offices, where (IBM says) they were unable to come to a nondisclosure agreement with DR and that Kildall never showed up for the meeting because he was flying his airplane [Kildall later denied this].  Because of this, on August 28, 1981, IBM signed a consulting agreement with Gates instead, where Gates agreed to develop an O/S for the IBM PC.  Rather than developing it from scratch, he paid $50,000 for QDOS, an O/S similar to CP/M, which Microsoft tweaked, renamed DOS, and sold to IBM.  On July 21, 1981, Kildall claimed to IBM that DOS infrinGary Kildall Photoged on his CP/M copyright, but settled his demand when IBM agreed to sell CP/M on its computers as well as DOS, giving users a choice of O/Ss.  Beginning on August 12, 1981, IBM announced PCs with CP/M O/S for $240 or DOS for $40. DOS outsold CP/M and went on to become the dominant O/S for PCs.  This from the book They Made America by Harold Evans.  For even more history and explanation, click HERE.

DOT COM:  (1) Anything relating to a business conducted on the Internet.  Derived from “.com,” which is attached to most website addresses for commercial websites (e.g., (2) Also, Kim Dotcom, see

DOT.NET (.NET):  This is a “platform” (i.e. a hardware or software “framework” such as a computer’s operating system or programming logoges) from Microsoft which supports what are known as “Web Services,’ which means the ability to use the Web rather than your own computer for various services.  It’s gone through lots of name changes.  .Net is supposed to make an entire range of computing devices work together and to have user information automatically updated and synchronized on all of them.  For example, Passport (Microsoft’s fill in the form only once) identity verification service, is part of .net.  Despite at least four versions, .Net isn’t yet nearly complete, which makes it that much harder to define.  In theory, applications written using .NET should interpret with those written in rival architectures, such as Java J2EE; however, this should not be confused with portability - .NET applications will only run on Microsoft platforms (XP, Windows Server, etc.) In actuality, .Net has caused so many problems that we usually remove it entirely, as it seems to cause other problems with the operating system.

DOT PITCH :  The distance, diagonally, between two phosphors of the same color on a CRT video display.  On LCD screens, however, the resolution of a monitor is simply the number of pixels contained in its matrix and is therefore pre-defined (e.g. a 17” LCD monitor is 1280 x 1024).  dot pitchSome manufacturers, however, have been known to improperly define dot pitch as the horizontal distance between phosphors, in an effort to increase their specifications.  DP times the viewable screen area equals the maximum screen resolution.  Generally, the lower the DP, the sharper the screen image. [Image Credit: bit-tech]

DoubleClickDOUBLECLICK:  Google’s display ad delivery system for web site pages.

DOUBLE ENTRY ACCOUNTING SYSTEM: I put this one in only because we receive so many questions about Quicken and MS MoneyPrograms like Quicken are single entry accounting systems.  They are for so-called “cash basis” taxpayers, and they record, in a register, expenditures and income at the time that the payment for the expense is made and the time that the income is received.  This might be fine for an individual, but not for a business.  Business use double entry accounting systems because they have to account for “payables” and “receivables”.  They show expenses when they receive the statement and income when it is billed.  Then, when the income check is actually received, the account payable is adjusted by the amount received, and when the bill is actually paid, the payable account is reduced by the amount paid.  Business, therefore, use a double-entry type program like QuickBooks.

DOWNLOAD: A verb, meaning to transfer data and files from one computer (usually a larger one) to another (usually smaller one), often over the Internet.  For example, one downloads MP3 music files from iTunes onto their computer or iPod.  The term also refers to the transfer from a computer to a peripheral device, like an iPhone.  See also, Upload.

DOWNSTREAM: Applies to the speed of an internet connection when downloading a file to your computer from another computer over your internet connection.  These speeds are typically higher than upstream transfers over the same network.

DOX, DOXXED:  A verb meaning to publish on the Internet private, personal information such as addresses, phone numbers, credit card information, workplace address or SSNs, usually with the malicious intent of allowing stalking of that individual, by effectively removing their anonymity.  Often done on online forums after a disagreement, it may be as benign as using that information to prank deliver 100 pizzas to someone’s address to seriously hacking and stealing a person’s identity.  Also, a practice sometimes used by ex-lovers who post revealing photos of their paramours on the internet as an embarrassment.  The term is said to be derived from the slang “dropping dox,” which was “an old school revenge tactic that emerged from hacker culture in the 1990s” (according to writer Matt Honan), much like writing someone’s name and number on a bathroom stall in high school.  [Some say it’s a contraction of “docs,” but it’s doubtful.] Although the practice of posting personal information during arguments and “flame wars” by Usenet posters was prevalent in the 1990s, starting around 2000, hackers like Anonymous (see Hackers) have used this harassment tactic as part of their arsenal.  Click this LINK for more information and examples.

DP:  See Dot Pitch, above; also sometimes called “pixel pitch”.  The smaller this number, which is expressed as .xx, the crisper the image.  The number itself represents the distance in millimeters between dots on a color monitor; .28 is normal for CRT monitors, LCD anywhere from .16 to .29.

DPI:  Dots Per Inch.  A measure of pixel density, which equates to resolution (clarity) of images.  See Pixels.

DPI:  Deep Packet Inspection.  This is a method that makes it possible for an ISP to identify, classify, reroute or block packets of specific data or code sent over the Internet.  This, as opposed to conventional packet filtering, which only examines the packet headers.  It is also a method used by some ISPs to track the web usage of its customers, usually to direct advertising to them.

DRAM:  A type of RAM that stores each bit of data in a capacitor within an integrated circuit and which, when charged, represent the two values of a bit, i.e. 0 or 1.

D RING:  A popular wire guide/carrier for telephone and computer data cable.  See also, Mushroom.

DRIVE:  See “HDD” and this LINK.

DRIVER:  The software which connects your computer to hardware that it needs to use.  The hardware can be internal (e.g. an audio or video card) or external (e.g. a printer or scanner) hardware, but the driver instructs the operating system about how to operate the hardware.  It is usually provided by the hardware’s manufacturer, although in later versions of Windows, the operating system itself includes many more hardware drivers.  Often, when hardware stops working, it’s because of a corrupt driver and you’ll have to reload it or an upgrade.

Android logo 2DROID:  Short for Android, noidGoogle’s smartphone operating system. The Droid character is shown on the left.  Not to be confused with the Noid (at right), the 1980s character which attempted to ruin Dominos pizzas.

DRM:  Digital Rights Management”.  A technology created by publishers of music, e-books and video to control the unauthorized duplication and distribution of their work product.

DROP:  When running cable, this refers to the cable running from the ceiling down the inside of the wall, usually connected to a punch down block and plate.  It’s called a “drop” because the cable is “dropped” down the wall for the connection. Sometimes referred to as a cable “run,” but this usually refers to the entire length of cable from the router or switch to the punch down block termination.

DROPBOX AND BOX:  See Cloud.  Free personal cloud storage.

DRP:  Disaster Recovery Plan.  Just like what it says, this is a plan to get your computers back up and running after a natural or man-made disaster damages or destroys your computer system.  Click for DRP considerations.

Drudge Report logoDRUDGE REPORT:  A news aggregation/blogging website started in 1997 by Matt Drudge and popularized by allegedly being the first news source to break the Monica Lewinsky scandal to the public after Newsweek declined to publish the story.  The site actually started as the supplement to an e-mail based newsletter focusing on Hollywood and Washington, DC before it took off.  Drudge is a right-leaning conservative aggregator.  For left-leaning aggregators, see Huffington Post.

Dr. WATSON: Of course, we could mean the U.S. telephone engineer (Thomas A., 1854-1934) who assisted Alexander Graham Bell in his experiments.  Or, possibly, the British doctor (John H.) who assisted the fictitious detective Sherlock Holmes. Or even the door-to-door salesman Thomas Watson who founded the company that became IBM.  However, we refer to a program error debugger (Drwtsn32.exe) incorporated into Windows (starting with the XP version) which creates a text file (Drwtsn32.log) which can be used by technical support to diagnose a program error, named we assume for its detective-like abilities like Holmes’ famous sidekick.  Don’t confuse this with plain old Watson, the IBM IA supercomputer.

DSL: Digital Subscriber Line, over which computers can connect to the Internet at high speed.  Click HERE for more.

DTMF: (Stands for “Dual Tone Multi-Frequency). Tone (as opposed to pulse) telephone dialing.

DTLS: (Stands for “Datagram Transport Layer Security). This is a protocol that is a derivation of the SSL protocol, providing the same security services but under UDP, which doesn’t suffer from the time delays associated with stream protocols, but may have to deal with packet reordering.

DUAL BAND: Refers to routers which operate at both the 2.4Ghz and 5Ghz band. 

DUAL BOOT: Configuring a computer to start up to more than one operating system.  It is not simultaneous, like a VPC, but either-or-or.

DUMB PIPE: A term used to apply to carriers like the phone companies which provide simply an undifferentiated connection or “pipe” to its phone and internet customers while others (like Apple or Google) provide apps and services to the customers.  Not particularly desirable to phone and internet companies, which have to differentiate their product based on speed and connectivity instead of unique software apps.  See Gen, 3G for more.

DUMB TERMINAL: See, workstation.

Dunbar photoDUNBAR NUMBER: A number postulated in the 1990s by British professor of evolutionary anthropology Robin Dunbar (popularized by Malcolm Gladwell’s book, published in 2000,  “The Tipping Point” about the dynamics of social groups), to be the the mThe Tipping Pointaximum number of people (which he generally believed to be 150) with whom one person can have strong relationships.  It is primarily based on the human brain’s neocortex size (an element of the Singularity as well) as well as studies of villages and settlements, and cannot ever be exceeded as the brain cannot be expanded.  Web developers find this number useful in determining how social networking and gaming sites can function with so many members; also the number has been applied to determine the maximum number of people in an office or in educational classes.  Related: Human limit to  multi-tasking.

DUPLEX:  A term meaning that both ends of a communication (telephone, computer, etc.) can simultaneously send and receive.  Ordinary telephone calls, for example, are full duplex.  Parties can both talk and listen at the same time.  Half-duplex, on the other hand, is still bi-directional but signals can only flow in one direction at a time.  Speakerphones are usually half-duplex - if you are speaking, you can’t hear anyone else interrupt unless you pause to let them speak.  Simplex is not duplex at all, but is a term for a communication signal which flows in only one direction, never back the other way. 

DUQU:  For more about this virus, click HERE.

DVD:  See CD/DVDs.

DVD-RAM:  Stands for DVD-Random Access Memory.  DVD-RAM disks can be recorded and erased repeatedly, but only on devices which support this technology, which isn’t available much any more.  It never really gained much support.

DVD REGION CODE:  Also Country Code, or Code Lock.  Primarily as the result of pressure from the movie industry, to preserve recording agreements and distribution rights, pre-recorded DVDs are given codes for each country that they are released in, requiring that they be played on a recorder matching the same region.  This is done because movies are released in different countries on different dates.  There are 8 codes, Code No. 1 for the U.S. and Canada, and the last two codes (7 & 8) for cruise ships and airlines.  Code 0 DVDs are uncoded and can be played anywhere.

DVI: Digital Video Interface.  This is a specification created by the Digital Display Working Group (DDWG) to accommodate both analog and digital monitors with a single connector.  There are three different DVI connector pin configurations:  DVI-A (analog only). DVI-D (digital only) and DVI-I (integrated, i.e. for both types of signals).  DVI connectors have lots of little pins, as opposed to standard VGA 41 pin connectors.  For photos, see connectors. And for more about current video connectors, click HERE.

DX:  See digital transformation, above.

DYNAMIC:  Changeable.  The opposite of static, which is fixed.  For example, while a static IP address never changes, a dynamic IP address has its lease renewed periodically and changes the address each time.





























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