“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.


E-:  Shorthand for “electronic”.  As in eBook (electronic book); eWaste (electronic waste); eMail (electronic mail), e-commerce (electronic business), e-signature (electronic signature) etc.

EAI:  Stands for Enterprise Application Integration, which is the systematic tying together of disparate applications, usually in an enterprise, through the use of middleware.

EAPExtensible Authentication Protocol. An authentication framework used in wireless networks for security purposes.  Defined in RFC 3748 (a “request for comments” issued by the Internet Society for inclusion in the Internet Official Protocol Standards), it is widely used; for example in IEEE 802,11 networks, the WPA and WPA2 standards have adopted EAP as official authentication mechanisms. Cisco has developed LEAP “Lightweight” EAP), which provides an even more secure username/password-based authentication for servers. And Cisco and Microsoft have developed PEAP (“Protected” EAP), which is also more secure than EAP, as it authenticates the server with a public key certificate and carries the authentication in a secure Transport Layer Security.

EARABLES:  The next stage in wearable computer technology.  Earables are worn-in-ear devices that serve specific purposes.  Like The Dash brom Bragi, which is a pair of Bluetooth headphones that not only are cordless but which can stream music, monitor your health, make phone calls and more, all while allowing ambient sounds so that the user can hear the environment without isolation.  Also, KUAI sports biometric headphones, and The Hear Active Listening System from Doppler Labs, which allows fine-tuning of what you hear to suit your taste.

earbudEARBUDS:  A device which fits into your ear and plugs via cable into the audio jack on your cell phone, pad or other device, so that you can listen to audio.  See also, cans, earables.

EASTER EGG:  See Easter Eggs, Features and Bugs.

eBay:  An American internet company that is the largest online auction and shopping website in the world.  It was founded on September 3, 1995 by a French-born Iranian computer programmer named Pierre Omidyar under the original name of AuctionWeb.  In September, 1997, the company officially changed its name to eBay.  Why the name?  Actually, eBay came about after Omidyar attempted to change AuctionWeb’s domain name to, representing the name of his consulting firm, Echo Bay Consulting Group, but because that name was already taken, he had to shorten it to  According to Wikipedia, the frequently repeated story that eBay was fabricated by a public relations manager in 1997 to interest the media was debunked in Adam Cohen’s 2002 book “The Perfect Store” and confirmed by eBay.  I had thought about establishing a separate page of this site discussing buying and selling on eBay, but someone else did such a great job that I refer you to links HERE and HERE, as well as the great tutorials on the eBay website itself.   See ePub.

ebookE-BOOK:  Stands for Electronic Book, an electronic version of a traditional print book that can be read by using a personal computer, smart phone or an appliance known as an eBook reader (such as a Kindle or Rocket) which is light and can store as much as one-half million pages of text and graphics.  eBooks can be purchased on DVDs or downloaded from sites such as Amazon or Scribd (stands for “scribbled”).  You can bookmark pages, make notes, highlight passages and save selected text on the readers.  See also, VOOK, TABLETS

ECCError Correction Code; also sometimes EOS (ECC-on-SIMM).  A significant improvement over parity for error detection in the transmission of data, ECC can not only correct single-bit errors “on-the-fly” but also successfully detect 2-, 3- and 4-bit errors, sometimes correcting them.  ECC uses a mathematical process in conjunction with the motherboard’s memory controller to append a number of ECC bits to the data bits so that, when the data is read back from memory, the ECC memory controller checks the ECC data read back as well.

ECHELON:  The largest electronic English-speaking spy network in history, run jointly by Australia, Canada, New Zealand, the U.K. and led by the U.SThese countries deploy electronic intercepts and satellites to intercept about three billion microwave, radio, satellite, cellular and fibre-optic communications daily, filtering them through supercomputers (known as “dictionaries”) for targeted addresses, phrases, words and voices for suspicious communications.  See also, Carnivore; PROMIS; PRISM; Room 641A, Laws, Social Networking, Privacy, How the NSA Does It.

Echo logoECHO(1) A service provided by Bright House Networks using MoCA to eliminate Wi-Fi deadspots through a scalable in-home Wi-Fi network.  It does this by adding a wireless access point anywhere in the house where there is a wired coax connection, not a traditional wireless repeater. (2) A wireless speaker and artificial personal digital assistant named Alexa, introduced by Amazon in 2015.  See FAQ 92.

ECMEnterprise Content Management.  A formalized way of organizing and storing the documents and other media of an enterprise.  ECM was originally defined in 2000 by the AIIM (Association for Information and Image Management), has been refined several times.

E-COMMERCE:  A general term which refers to “electronic commerce,” which is the buying and selling of products and services over the Internet through computers and other similar devices (e.g. smart phones).

ECP:  A standard bi-directional signaling method for networked printers.  EPP, below, is for non-printer peripherals.  See printers, settings.

EDA:  This could mean one of two things:  (1) Electronic Design Automation - The latest acronym for using computers to design electronic circuits (e.g. on chips or circuit boards), which is a merger of computer aided design (“CAD” to create the schematics) and computer aided engineering (“CAE” to analyze the created designs).  Also (2) Enterprise Data Access, which in larger organizations with multiple databases and file types, provides a way for users to access a common interface which will access all of them.

EDGE BROWSERMicrosoft’s replacement, starting with Windows 10, for the aging and buggy Internet Explorer browser.

EDGE CASE:  A situation that occurs only at an extreme operating parameter and not in the usual course of operation.  For example, a stereo speaker may distort sound, but only when played beyond its maximum rated volume.  Edge cases may be either anticipated or a complete surprise (or, in the extreme, a   Black Swan).  A corner case adds to this by causing the situation or problem when multiple parameters occur, even though each parameter may be within its specified range.  So the speaker could distort sound due to a combination of volume, humidity and static, even though each of those elements is within its individual range.   A boundary case refers to the behavior of a system when one of its inputs is at or just beyond its minimum or maximum inputs.  All of these cases are useful in properly designing algorithms which will function properly within all possible limits, not just the basic situations, but up to and including the edge, corner and boundary cases if necessary.

EDGE COMPUTING:  See Fog Computing.

The “edge of the Internet”: Where a network infrastructure connects to the Internet.

thomas edisonEDISON, TH0MAS ALVA:  (1847-1931) “The wizard of Menlo Park (NJ)”. He is important because almost everything computer, from Big Iron mainframes to cell phones we use today require some form of electricity.  An American inventor responsible for the electrical grid, phonograph, motion picture camera, fluoroscope (the x-rays from which killed his assistant, Clarence Dally), the first tattoo machine, long-lasting light bulb and many other items which have made our daily life much easier.  He was self-taught, a relatively poor student, nevertheless holds 1,093 patents in his name, much of his work the outgrowth of his early experience as a telegraph operator.  But his quip that “I have not failed - I’ve just found 10,000 ways that don’t work” is true:  His central automatic vote recorder (his first invention flop), an electric pen, a talking doll, concrete homes and furniture, the Edison Home Service Club and many other inventions were colossal failures.    He built his first home lab at 10, and did have a lab in a boxcar at 12 when, the story goes, he was smacked in the ears by a conductor for starting a fire, leading to his deafness shortly thereafter.  (Or was it actually scarlet fever?) He also published the first newspaper from a train, the Grand Trunk Herald using a printing press in the baggage car.  The story continues:  When he was 14, he saved 3 year old Jimmie MacKenzie from a runaway boxcar and Jimmie’s father was so grateful that he taught Edison how to operate the train’s telegraph machine.  However, he was fired when one of his lab experiments leaked sulfuric acid through the floor onto his boss’ desk below.  Edison’s first two children, not surprisingly, were named Dot and Dash.  And he proposed to his second wife using Morse code (mostly due to his deafness).  His “War of the Currents” with Nicola Tesla and George Westinghouse about whether AC or DC current was best for long distance transmission was lost, and all transmission is now AC today, as DC required all houses to be located within a mile of a substation.  Tesla was employed by Edison at a cost of about $18/week but never collected for his work proving AC superior, causing years of bad blood between the two.  Edison went so far as to claim that AC was unsafe for home use and could lead to electrocution, staging a demonstration with a rogue circus elephant named Topsy showing the electrocution, a precursor to Edison’s invention of the electric chair.  Click HERE for the video. 

EDISON:  See Raspberry Pi, click HERE for more.

EDP:  A type of file (“attachmate extra” file) which is often unreadable in Windows without changing the file program association.

EDREnhanced Data Rate.  See Bluetooth.  This is an optional part of Bluetooth that provides a faster rate and sometimes improved battery life.

EDSAC:  Just like the Eniac (below; see photo at Bartik), the British Edsac (acronym for Electronic Delay Storage Automatic Calculator), built in 1949 was a cumbersome first generation computer, developed during wartime by women like Dorothy DuBoisson, Elsie Booker and Margaret Bullen, who created Colossus, a code breaking computer.


EDUTAINMENT:  A portmanteau of “education” and “entertainment” which refers to software such as videos that are designed to teach something.

EEE:  Shorthand for Energy Efficient Ethernet or the 802.3az specification.  EEE relies on feature-compatible chips known as “PHY chips” which are installed at both ends of a network link that can monitor link traffic and drop connections into a low power state when no data is flowing, a condition that exists about 90% of the time.

EEPROMElectrically Erasable Programmable Read Only Memory.  As opposed to EPROM, which is erasable by ultraviolet flash to reprogram, EEPROM is electrically erased by a voltage surge.  See also, Firmware.


EFS:  Encrypting File SystemA protective encryption system built into Windows XP Pro and Vista Business, Enterprise and Ultimate releases.  EFS’ successor, Bit Locker, is used in Windows Vista Ultimate and Enterprise versions and Windows 7.

EGA:  See, COLORS, VGAEnhanced Graphics Adapter, allows up to 16 colors at 640 x 360 resolution.

EGG:  See, Twitter

EHR:  Electronic Health Record. Personal medical records which are kept digitally.  The HITECH Act (Health Information Technology for Economic and Clinical Health, part of the American Reinvestment and Recovery Act of 2009) dictates that U.S. hospitals must implement and demonstrate what is called “meaningful use” of electronic medical records by 2015.  See LAWS for more.

EIA:  Electronic Industries Alliance - Along with the TIA, provides best practice guidelines for cabling infrastructure, among other things.

EIGHT-THREE (OR “8-3”) FORMAT:  References the format first used by IBM for the names in the Microsoft FAT file system, which limits file names to eight characters plus a three character extension, sometimes modifying longer file names by using the tilde after the first six characters followed by a single digit (e.g. “MICROS~1.TXT”). See also, Extension, below.

EISAExtended ISA - see ISA.

ELElectroluminescent.  When a material emits light in response to the passage of electricity through it.  They save power, produce even output and last for a long time.  Common uses can be as simple as flat panel night lights to billboards to automobile instrument panels to Tron-like outfits.

ELASTICITY:  As defined by NIST (see Associations), this means the rapid, sometimes automatic, ability to scale out (expand) a network.

ELECTRONIC:  As opposed to “electric,” which means only that the device operates using electricity.  Electronics takes this one step further by using electricity to power components such as  capacitors, (micro)chips, resistors, transistors, transformers, thermistors and microprocessors without the use of mechanical elements.  For electrical terms, see voltage, amperage, polarity, resistance and resonance.

ELECTRONIC ENTERTAINMENT EXPO (a/k/a “E3”):  An annual convention started in 1995 at the Los Angeles Convention Center for computer and video gamers presented by the ESA (See Associations).

ELECTRONIC RUST:  See, Surge Suppressors.

ELEVATED MODE:  See, Administrative Mode.

ELEVATOR BUTTON:  The square button on the right side of a window, in between the up and down arrows, used to navigate vertically by grabbing the box with the left mouse button and dragging it up and down.

ELIPSES:  Three periods together (“...”) sometimes used in arguments or formulas.

ELLISON, LARRY:  See, Oracle.

ELM:  Portmanteau of ELectronic Mail.  Originally one of the popular e-mail clients, using a text-based interface and freely available source code for Unix.  Still used by some providers, like

Elo photoELO RATING:  A method for calculating the relative skill levels of players in competitive games.  Named after its creator, Hungarian born American Physics professor Arpad Elo (1903-1992; pronounced “e-e-e-lo”), the system began implementation in about 1960 and has been expanded from its original adoption by the World Chess Federation to encompass most other competitor vs. competitor games, including online gaming and World Football.  As players’ continue to play more games and update their experience, their rating varies.  An example would be the rating of 2300 for Demis Hassabis, gamer and now neurology AI expert when he reached master chess standard at the age of 13.  The scores run from less than 1199 for beginners, then increase all the way to Chess God for scores greater than 2800.  For how it’s actually calculated, click HERE


EMBEDDED COMPUTER:  A computer with a specific function, such as those found in cars, appliances, TV/VCRs, etc.

EMBREE:  See Ray TracingA free graphics library released by Intel for use with ray tracing to produce high resolution graphic images with parallel processors.

EM DASH (Sometimes M-Rule):  A typographical symbol which has the horizontal length of two or three standard dashes (i.e. “- -” or “---”) commonly used to demarcate a parenthetical thought. Distinguishable from the N-Dash, which is slightly shorter, although longer than an ordinary dash, and which is used - - always with spaces in running text - - for a similar purpose.  Further, some languages (such as French) use the horizontal bar or quotation dash to introduce quoted text, although it is not used in English.  Confused?  Me, too - - they all look the same.

email-envelope-graphic-300x228E-MAIL:  [Sometimes just “email”].  The exchange of computer generated and stored messages trough telecommunication, over the internet, either directly or through an ISP.  Click HERE for a detailed discussion about POP and IMAP.  See also, MX record, Postini.

EMI:  Electromagnetic InterferenceDirt” in the electrical current that may hurt equipment performance and cause errors to sensitive components and measurement equipment.  Usually caused when the radio waves of one device distort the waves of another (e.g. wireless computer network disturbs cellphone communication).  Fluorescent lighting often causes EMI.  See Raceway.

EMMEnterprise Mobile Management.  Uses APIs similar to those in iOS, Android and Mac OS for management and security APIs.  But is nowhere as robust as Windows EMM, such as set up kiosk mode or enable local encryption, which must still be done with SCCM (System Center Configuration Manager).

EMOTIONS ANALYTICS:  Closely related to facial recognition, this is software which uses live or captured video of facial expressions to track various emotional states.  This field was pioneered in the 1970s by American psychologist Paul Eckman and has been improved to the point of application by market leaders Emotient, Affectiva and Stoneware and an increasing group of others.  Companies like Unilever and Coca-Cola use EA to understand customers’ likes and dislikes when they view ads or purchase products to tailor their marketing campaigns.  Emotient has used the software to study how spectators respond to sports activities, and Stoneware’s product is used in over 1,000 classrooms in the U.S. and Canada to track students’ attention and reactions during classroom instruction.  It can be used in PCs, smartphones, cars (e.g. to alert drivers if they become distracted) and many other devices.  A sub-division of EA analyzes vocal intonationsBeyond Verbal, a 3 year old Tel Aviv startup, has designed software which identifies some 300 mood variants in more than 40 languages with about 80% accuracy.  Even Microsoft has developed it’s own prototype apps that track emotions via a skin sensor through an activity band incorporating a heart rate monitor.  The app alerts users when stress levels are high, sometimes using a crystal on the desktop which changes color like a mood ring (although workers tended to hide it when their boss came by).  As with other such devices, there is the usual debate about whether they violate individual’s privacy if used without up-front notification and consent, whether they’re in public or not.

EMOJI:  The Japanese term for emoticons (below).  Translation emoji bowing= pictograph.  Emoji are specific to Japanese culture (such as bowing), not like the more universal emoticons, and are often standardized and built into Japanese cell phones.  (Google Android phones have settings for Emoji [at heart emojiSettings>Labs]).  For the first time, in 2014, the Global Language Monitor (see Associations) announced that an emoji, the heart-ing emoji was the word of the year.  (Shown at left.)  See emoticons, below.

EMOTICON:  An emoticon (contraction of “emotional icon”) is a short sequence of letters and symbols, usually emulating a facial expression, that complements a text message, demonstrating the writer’s emotional state.  The first well-known emoticon was the “smiley” which allegedly became popularized as far back as September 19, 1982 by Prof. Scott Fahlman of Carnegie Mellon U., although it was invented much earlier (in 1963) by Harvey Ball of State Mutual Life Assurance Company for use in an employee morale-building campaign at that company. When it entered the public domain, it became used by everyone to this day.  Click HERE for a list of smileys.  Anmated emoticons are sometimes described as “emoji”;  Japanese emoticons are known as “kamaoji”.  All are shortcuts to convey a emotional state, often far better than mere words.  Some can be quite complex in their construction. And then there are “stickers,” custom pictures used in some instant messaging clients like Facebook (or AOL) Messenger, which are fully specific to the app and can’t be cut-and-pasted elsewhere unless they can first be saved as an image.   Finally, there are the familiar dingbats, which are more standardized in accordance with the well-established set of glyphs available in most laser printers using the Unicode Standard.  The flexibility allowed for emojis, discussed below, isn’t present. 

DIFFERENCE BETWEEN EMOTICONS AND EMOJIS:  Emoticons are typographical representations (done with a standard keyboard) of a facial expression and are conveyed in a text-only medium, as ;-).  So far as the Internet, it is widely considered to have been invented in September, 1982, when Dr. Scott Fahlman, a computer professor at Carnegie Mellon U. suggested that the expressions ;-) and ;-( could be used to distinguish jokes from serious statements online and thus the portmanteau of “emotional icoemojin” was established. In contrast, emoji (at right) are actual graphics, created in Unicode, in the late 1990s by DoCoMo, the large Japanese Internet provider , and is a contraction of the words “e” and “moji,” basically translated as “pictograph”.  While emoji are treated by a computer as letters from a non-Western language, it must be supported by software and each company must provide its own interpretation of what the emoji looks like, so it may actually look different for every browser.  (For example, the “dancer” emoji looked like a female flamenco dancer on Twitter and Apple, but originally like a male disco dancer on Google.) 

EMPATHY:  An instant messaging client for Gnome in Linux.  See Linux.

EMR:  Electronic Medical Records.  See the Hitech Act in Laws.

EMTA (E-MTA):  Media Terminal Adapter.  A combination cable modem and telephone adapter, frequently used in those 3-in-1 cable and phone installations (i.e. telephone, internet, television through one ISP).  This is a piece of hardware that connects a computer to the Internet in those instances where there is a digital signal (such as with ISDN, DSL) and therefore is no need for a traditional analog modem since there is no analog signal.  Also used for VoIP applications, either where it is actually embedded into a DOCSIS type modem, or as a separate VoIP appliance that connects to the cable modem.

EMV:  A type of credit card called a “chip card,” used in most of the world, which uses an embedded chip rather than a magnetic strip for transaction processing.  Rather than being “swiped,” it is “dipped” into the card processor and left there for the entire transaction, as the reader and the card communicate back and forth.  At completion, the chip generates a unique code for each transaction.  It’s more secure than magnetic stripes because those codes are permanent and can thus be stored by hackers for later use. Because of this additional security, sometimes it takes somewhat longer to process the transaction.  The standard is managed and maintained by EMVCo., which was formed in 1999 by Europay, MasterCard and Visa, from which it derives its name.  See also PCI.

UPDATE: Starting October 1, 2015 banks require that  U.S. merchants make the transition to EMV as well.  If, by that date, they do not have transaction scanners to read the chip cards, they could be liable (to the bank) for any fraudulent transaction using a chip card that was not processed with the new scanners.  It is expected that the full transition will still take about 3-5 years to complete, as major food and store chains will have quite a bit of adjustment and cost to accomplish this.  And literally years for all banks to issue the new type of chip cards to millions of customers.  Banks claim that they have made this move because almost half of the world’s credit card fraud occurs in the U.S. even though only a quarter of the world’s transactions are made here, therefore they need better security. But they still complain that the signature-based verification is insufficient protection and instead are campaigning for PIN verification. There are some exemptions, but most stores and restaurants will have to at least modify (by add-on readers and possibly additional software) their POS systems.  Faced with the slowness of adoption (by March, 2016 only 37% of U.S. businesses accepted chip cards), banks are now saying that the October 1st deadline wasn’t firm. Click HERE for the key dates for EMV, listed by Verifone.

ENABLED:  Refers to hardware that has been found in a device and is connected.  Bluetooth, for example.  The opposite of disabled, where a device may be found, bot not connected.

ENCAPSULATION:  See, TunnelingHiding code inside of a different protocol so that it can be transmitted.  For example,  hiding IPv6 inside IPv4, so that it can be transmitted over the Internet.

ENCODE:  To convert data to machine readable format; more specifically, to convert an analog signal into a digital signal as the final of three steps (sampling, quantizing, encoding).

ENCRYPTION: Defined:  This is the process of transforming information (referred to as “plaintext”) to make it unreadable to anyone except those possessing special knowledge (referred to as a “key”).  Long used by governments and the military to facilitate secret communication, it is now commonly used in wireless computer devices as well.  To learn more, click HERE. See also, for example, CHAMPOLLION, JEAN-FRANCOIS

ENDPOINT:  Usually refers to the farthest point on a computer on the network, therefore usually the workstation.

ENERGY STAR:  A joint program of the U.S. Environmental Protection Agency and the U.S. Department of Energy certifying energy efficient products and practices.  Look for the logo at the right on such items as computer monitors.

Englebart DouglasENGELBART, DOUGLAS:  [1/30/25 - 7/3/13] The actual inventor of the computer mouse, hyperlinks and GUI.  He was one of the team responsible, along with Intel co-founder Gordon Moore, for the development of what became known as Moore’s Law in the 1960s, which basically posits that computer power increases exponentially while costs fall inversely.  Also, he was a proponent of computer augmented reality (i.e., computers “bootstrapping” human intelligence) vs. computer AI (“replacing it”; see also John McCarthy).  After working at NACA (NASA’s predecessor), then the Stanford Research Institute (“SRI”), he formed his own lab, the Augmentation Research Center, which was partly responsible for development of Arpanet, the government agency that was responsible for the Internet.  [For more discussion about Engelbart’s inventions, see Mouse.]

ENGINE:  The software that drives a particular program, as in the “browser engine”  (See BROWSER).  Not to split hairs, but engine specifically refers only to the “core” of the program, and not the “peripheral” aspects of the software, such as the skins or look-and-feel of the program.

ENHANCED KEYBOARD:  Also referred to as the “101-key IBM Enhanced Keyboard,” introduced in 1986 to improve over the old IBM 84-key AT keyboard, this keyboard includes a number pad and shortcut keys for cursor movement.  You should note that almost any keys can always be “remapped” by software.

ENHANCED MITIGATION EXPERIENCE TOOLKIT (“EMET”):  A free utility from Microsoft that helps prevent memory corruption vulnerabilities in computer software from being exploited.  In other words, it strengthens software and hardens it against attacks and intrusions.  It has gone through several revisions since its introduction and is continually updated. 

ENIAC: Electronic Numerical Integrator and Calculator (some say “Computer” but its designers didn’t call it that (see below)), generally regarded as the first electronic computer. Built in 1945, it was a beast of a machine; it contained 17,468 vacuum tubes, 70,000 resistors, 10,000 capacitors, 6000 manual switches and 5 million soldered joints, covering 1800 square feet of floor space, weighing some 30 tons and consuming  1600 kilowatts of power to run at only 5 kilohertz (less than the power of a smart watch; most desktop computers today run at 4+Ghz!). It was developed by Army Ordnance Balistic Research Laboratory to compute firing tables, which detailed trajectories for shells and bullets, during WWII (see ENIAC Programmer Group, below). But is was not a stored-program computer like the ones we are familiar withENIAC2 today (see Computer, Von Neuman architecture), but was more like a collection of electronic adding machines (hence the “C” for calculator) which could be programmed to complete a task.  It was initially developed by John Mauchley (see reference to wife Kay Mauchly McNulty Antonelli below) and John Prosper Eckert who built on the ideas of John Atanasoff to use vacuum tubes to speed up the calculations.  Interestingly, Dr. John Von Neuman also made several modifications to the ENIAC, notably that switches rather than pluggable cables were used to control code selection, also the addition of a converter code to enable serial operation. Later Eckert and Mauchly started their own computer company, launching the BINAC (BINary Automatic Computer) which used magnetic tape to store dataEckert-Mauchly Computer Corporation was then purchased in 1950 by Remington Rand Corp., changing the name of the computer to UNIVAC (Universal Automatic Computer).  Remington Rand merged with Sperry Corp. in 1955, forming Sperry-Rand Corp., which in turn later became Unisys when it merged with Burroughs Corp.  See also Bartik, Edsac, Fortran, Old Computers.  For an excellent article (with photos) about the programming of the ENIAC, click HERE.  However, there was never a “BRAINIAC” computer. Rather that name was a contraction of “brain” and ENIAC, used to refer in the 1950s to those who later become known as Geeks, referencing their superior brain power.

ENIAC PROGRAMMER GROUP: A group of six women who were the original programmers of the ENIAC computer (above) during WWII.  Because of their rare expertise in mathematics, they were recruited by the U.S. Army to work at the Moore School of Electrical Engineering at the University of Pennsylvania, which was associated with the U.S. Army Ballistics Research Laboratory in Aberdeen, Maryland.  Originally called simply “Computers,” they included:  Kathleen McNulty Mauchly Antonelli (at one time Mauchly’s wife),  Jean Jennings Bartik, Marlyn Wescoff Meltzer, Frances Bilas Spence, Ruth Lichterman Teitelbaum,  and Frances “Betty” Snyder Holburton.  According to Kay McNulty Mauchly Antonelli, the publicity photos taken in 1946 didn’t actually show the real women, but rather so-called “refrigerator ladies” (i.e. models) who were merely posing in front of the massive computer.  A current photo, sixty years later (5 of the 6, anyway), is displayed below.  Others involved in the initial phases of the programming were Frances Holber and , Gloria Ruth Gordon and Esther Gerston.  All were inducted into the WITI Hall of Fame in 1997.  See WOMEN.  Of course there were over 100 initial programmers; not all were women.

Eniac programmer group today

Left to Right:  Kathy Kleiman, Jean Bartik, Marlyn Meltzer, Kay Mauchly Antonelli & Front: Betty Holberton.

ENTERPRISE:  Basically, another term for business (as opposed to residential) software.  Enterprise software is software used by businesses.  Enterprise 2.0 comprises social software as used in the business enterprise, much like Web 2.0.

ENTROPY:  As related to computers, entropy is a numerical measure of the uncertainty of an outcome.  It is actually a measure of how much information you are missing.  If you want to know where someone lives, you have high entropy (not enough data, too many variables) if you only know that they live in the United States.  Entropy becomes lower if you find out that they live in New York, even lower if you find out that they live on the lower east side, and even lower if you find out their actual address.  In each stage, you are missing less information.  This is a product of Claude Shannon’s work at Bell Labs, who created an equation to determine the  informational content of a precise piece of communication, postulating that the informational value of a message (whether it is spoken, written or transmitted over the internet) is a function of how much the recipient already knows.   If an outcome is highly unpredictable, a message communicating the outcome carries more information (and requires more bits) than if the outcome is more predictable.  Shannon’s entropy allows programmers to create software that packs the most important information into the smallest file size.  Let’s be more precise, by example:  You can post a selfie with a blank background.  Or it can be taken with the Pope, or at Disney.  The one with the background may be a larger file, but it allows a programmer to figure out how to communicate with you more accurately and efficiently. That’s how entropy works. Similarly, computer passwords with more “strength” have high entropy, supposedly making them less hackable.  (But see HERE for the new reality.)

The broader scientific explanation is that entropy is the theory that everything in the universe eventually moves from order to disorder.  Entropy is the measurement of that change.  It wRudolf Clausiusas first described by the German physicist Rudolph Clausius (1822-1888) in 1868, when he founded the second law of thermodynamics, which was later to become known as the “law of increasing entropy” or the  “arrow of time”.  The most common explanation of this principal is the example of ice (ordered) melting into water (disorder).  But entropy is a complex concept (click HERE for what claims to be a simple explanation!) See also, for example, PRNG.  Also, chaos theory.

EPEAT_logoEPEATElectronic Product Environmental Assessment Tool.  This is a ranking (bronze, silver and gold) developed between 8/2002 & 5/2006 of the green attributes of computer equipment, considering 51 specific criteria for a device’s power management capabilities, hazardous materials, recyclability, ease of disassembly and other factors. It is managed by the Green Electronics Council.

EPICElectronic Privacy Information Center, a private privacy organization which sometimes files complaints with the U.S. Federal Trade Commission about such social networking sites as FaceBook and Buzz about the lack of protection of users’ private information.

EPP:  A standard bi-directional signaling method for non-printer peripheralsECP, above, is for printers.  See printers, settings.

EPROM:  An Erasable Programmable Read Only Memory chip, which can be erased (by exposure to a burst or “flash” of ultraviolet light) and the reprogrammed for upgrades or changes in hardware or software.  Such chips are contained, for example, in BIOS, hence the term “flashing the BIOS”. See also, EEPROM, above.

EPUB:  A popular open e-book standard.  It is the file extension of an XML format for reflowable digital books and publications.  It is composed of three open standards, the Open Publication Structure (“OPS”), Open Packaging Format (“OPF”) and Open Container Format (“OCF”), all produced by the International Digital Publishing Forum (“IDPF”).  Barnes & Noble’s Nook uses the ePub standard.  Other eBook readers , such as the Kindle use different, sometimes proprietary formats.

ERGONOMICThe applied science of equipment design, as for the workplace, intended to maximize productivity by reducing operator fatigue and discomfort. Also called biotechnology, human engineering, human factors engineering.   Example: the curved Microsoft ergonometric keyboard.

ergo keyboards

ergo mouse

ergo shuttle

floating arms keyboard

floating arms

ERP:  This stands for “Enterprise Resource Planning”.  Just like it sounds, this includes an “information system” that “integrates” all of the operations for an “enterprise”.  In more plain English, it is a computer that manages everything possible for a company, from planning, manufacturing, scheduling, advertising, customer support, etc.

eSATAExternal Serial Advanced Technology.  This is an EXTERNAL interface for SATA technologies, competing with Firewire 400 and USB 2.0 to provide fast data transfer speeds for external storage devices.  See, SATA and Links. Requires a slightly different connector and cable than internal SATA drives which connect directly to the motherboard. See, photos of cable connectors.  Also, eSATAp (a/k/a Power over eSATA, eSATA/USB Combo or eSATA USB Hybrid Port (“EUHP”)) is a combination port into which either eSATA or USB can be connected.  Not officially approved, use at your own risk. 

eSCORE:  See Score.

eSIGNATURE (a/k/a DIGITAL SIGNATURE, CRYPOTOGRAPHIC SIGNATURE):  An electronic rather (than a handwritten) signature that can be used to authenticate the identity of the sender (if a message) or signer (if a document).  eSignatures are easily transportable, cannot be imitated and can also be automatically time-stamped, making them quite secure.  They can be used with both encrypted and unencrypted messages and are often recognized as authentic for legal documents and filings just like the older traditional forms of execution.  (see LAWS for more about the legalities.)  Use of an eSignature, which is issued by a public-private key authority) proves the authenticity of the sender and also that the data was unchanged after its transmission.  (On web portals, eSignLive API and Java SDK are commonly used to provide this capability.)  It is NOT the same as a PKI “digital certificate,” as it is only issued for each transaction.  Here’s how it works:  Suppose you finally get that offer from a major league ball club.  You want to send a contract to the league’s lawyers, but over the Internet.  First you copy, then paste the contract into e-mail.  Then, using special software, you obtain a message hash of the contract, using a private key that you have previously obtained from a public-private key authority to encrypt the hash, which will then become your “digital signature” of the message.  (Note that, unlike your handwritten signature, your digital signature will be different for each message you send).  At the other end, the league’s lawyer will make his own hash of the received message, then use your public key to decrypt and view the message. If it’s been tampered with, he won’t be able to see it.   Sounds more complicated than it really is.

ESDElectrostatic Discharge.  Essentially, a “spark”.  The sudden and momentary discharge which is created when a current flows between two objects at different electrical potentials.  This can be particularly damaging to electronic circuit boards and other computer componentESD Bracelets.  Computer technicians routinely wear ESD “bracelets” (see right) on their wrist and clipped to a ground in order to prevent ESD, which can completely ruin a computer if not properly protected.

ESI:  Electronically Stored Information.

ESOLANG:  Esoteric programming language.  Unlike the programming languages used by developers to write their software, this type of programming language is designed to test the boundaries of programming language design.  It is not intended for general use or mainstream programming, rather for use by hackers and the like.

E-STEWARD:  See, Green.

ETHERNET: Ethernet is a network standard of communication using either coaxial (10 baseT) or twisted (4) pair cable (Cat [“category”] 5, 5e, 6, 6a, 7, 7a,8; see chart below), known as UTP (“unshielded twisted pair”) copper cable.  Generally, there are 6 twists over 5 centimeters using 24 gauge AWG copper wire.  The higher the CAT level, the higher the protection from electrical interference, which is reduced by more twists of the cable and other insulators within the cable.  Ethernet is set by IEEE Standard 802.3, which includes dozens of standards.  Click HERE for photos of Ethernet cable and connectors.  Depending on the cable, ethernet transmits data at a rate of 10, 100 or 1000 million bits per second or Mbps.  In practice, though, Ethernet can’t really move data that fast, because data must be transmitted in packets of no more than 1,500 bytes.  So, on a 10Mbps system, a 150K file would have to be split into 100 packets.  The actual technique for controlling the flow of information over network cables is called CSMA/CD.  And in some instances, ethernet cables can also simultaneously run power to the connected devices, using what’s known as “power over ethernet” or PoE.  See also, “Ten Base” for explanation of older technology; and GbEFibre cabling, which is not Ethernet cabling but can interface with the Ethernet network, for links between edge and core switches, comes in two general types, Multi-Mode (“MMF”) and Single Mode (“SMF”); the SMF being more expensive, but thinneethernet symbol2r and capable of higher transfer rates. See IEEE, as well.  See also, GbE.  The universal ethernet symbol is shown at right.

A LITTLE ETHERNET HISTORY:  The acknowledged Bob Metcalf photoinventor of Ethernet was Bob Metcalf.  In 1972 he proposed a computer network connected with coaxial cable and later founded the digital electronics manufacturer 3ComXerox/PARC invented the first ethernet-only cable known as “X-Wire” in 1968, which ran at 10Mbps.  After that, in 1983 the IEEE formally approved the 802.3 ethernet standard, used ever since.  The first ethernet adaptor card was introduced by Intel in 1981. 

Over time, cable has evolved from 10BASE-5 “thicknet to 10BASE-2 “thinnet to unshielded twisted pair cable used for phone cables to 100Mbps 100BASE-T (IEEE standard 802.3u, 1995) to 10BASE-F (ethernet over fibre, 1994) to Gigabit ethernet (1000Mbps (1Gpbs), 1999; most common today) to the 10G ethernet (IEEE 802.3ae, 2002)  to 40/100G (802.3ab, 2010) to the proposed 400G by 2017.  In late 2016, the IEEE ratified a new Ethernet specification (IEEE P802.3bz) that defines 2.5GBASE-T and 5GBASE-T, boosting the  current top speed of traditional ethernet five-times without requiring the tearing out of some current cabling (see Associations for IEEE and NBASE-T Alliance). And so on...









16 MHz

100m (328 ft)

10Base-T, up to 10 Mbps

Now mainly for telephone cables



20 MHz



Rarely Seen



100 MHz


100Base-Tx, ATM, CDDI, up to 100 Mbps

Common for current LANs



100 MHz


1000Base-T, up to 1000 Mbps

Common for current LANs

Cat6, 6A


250 MHz


10GBase-T - Gigabit Ethernet, up to 10Gbps

Common for many LANs

Cat7, 7A


600 MHz


Gigabit Ethernet and more?


Cat 8




40Gb server networks



Credit: BSRIA/Tech Republic

e = “Enhanced” - supports networking up to 1000Mbps, vice 100Mbps, by using all four wire pairs, not just two.

a =   “Augmented” - Pretty much the same as “e,” it effectively doubles transmission capability, but is large and hard to work with (heavy and a larger turn radius), as it has a central plastic support inside the core of the cable.

Cat7 (a/k/a “Class F”) is defined by a different standards body than Cat 3,4,5 and 6.

Cat 7, 7A and 8 cables can double their speed if dual-paired and Siemons TERA connectors are used.

Cables can be mixed, so long as the minimum cable category will support the maximum speed of your network.

For a detailed discussion of only Cat copper cables, click HERE.

EtherNet/IP:  Click HERE.

EULA:  End User License Agreement.  This is the boilerplate legalese that pops up just before you install software.  That would be the screen that you have to click “I Accept” to before the software will install.  It’s a good idea to read through the EULA to check for hidden installs of spyware, trialware, adware and hidden Internet browser toolbars that you might not want installed simultaneously with the desired program.  Sometimes (e.g. with Adobe) you can uncheck the boxes; others are “contracts of adhesion,” i.e. you can’t change the terms or you won’t get the software.

Euro symbol

EURO:  The symbol for the euro currency, sometimes found on foreign language keyboards.

EVDO:  Evolution-Data Optimized.  A 3G digital service provided by CDMA cellular carriers such as Verizon and Sprint.  Don’t confuse this with the commonly used “EVOO” which stands for Extra Virgin Olive Oil.  Too much cooking channel??

EVERNOTE:  See also, OneNote, Google Keep.  An everything-in-one-place cross-platform personal organization app that is hyped by its creators as your “external brain”.  Developed in 2008, it has over 100 million users around the world (most popular in Japan), most using the free version of the app, but others who pay the Evenote logo$45/yr or $5/month ($10/month for business users) for the additional “fremium” features such as separate “notebooks” and more cloud space.  Basically, users upload all types of ”notes” (personal and/or business information, data, media or thoughts) into the Evernote cloud in no particular order, because the search feature for the software is so good that it can locate whatever you may be looking for in a second.  In October, 2014, CEO Phil Libin announced a major expansion and redesign of the software providing greater collaboration for sharing and editing presentations, web clipping from outside sources, work chat, and more.  See  for more.  Below, the comparison chart from TechRepublic (by Patrick Grey, 4/2/14) for both Evernote and OneNote:

evernote vs. one note

E-WASTE: Electronic waste.  The toxic waste that is generated when computers (as well as other electronic appliances such as TVs, VCRs, Stereos, copiers, fax machines and cellphones) and their components (especially CRT monitors) are disposed of, releasing dangerous levels of lead, cadmium, mercury, beryllium and brominated flame retardants into groundwater or the air.  The sheer volume of this waste, and it’s mass export to developing countries, is causing huge human and environmental issues.

EXASCALE (COMPUTING):  Computing systems capable of at least one exaFLOPS (each exaFLOPS is a thousand petaflops or a quintillion, 1018, floating point operations per second (“FLOPS”).  See, world’s fastest supercomputers.

EXCEL:  The spreadsheet program included in the Microsoft Office suite.  See Office for more.  As it evolves, many capabilities are quite amazing.  In For example, the Stock Connector imports financial market data into a spreadsheet and updates it, filters, sorts and generates reports from it.  In other words, the data that Excel works with isn’t just generated on a computer, but can also be imported from other sources.

EXCHANGE: A Microsoft program popular with businesses that includes messaging and groupware for Windows Server systems. With Exchange, for example, users can get their Outlook e-mail simultaneously from anywhere and view it on a variety of devices (such as iPads) showing mail rules, folders, flags, contacts and the like, just as they would on their office computer. See also PST.

EXCHANGE ACTIVE SYNC:  See discussion under e-mail.

EXCHANGE WEB SERVICES:  See discussion under e-mail.

.EXE: A Windows, DOS or other O/S file that ends with the .exe extension, also known as an “executable file” because most often when one clicks on an .exe file, it installs and runs programs. It can be dangerous because some .exe files may contain malicious viruses.

EXECUTE: To start, as in to run the .exe file for a program.

EXPLOIT: An attack on a computer system which takes advantage of a particular vulnerability, like a known bug in a program or operating system. See also, Zero Day Exploit, SPYWARE.

EXPLORER: PCs actually have two “explorers,” which is the purpose for this definition.  The first is the well-known Web browserInternet Explorer.”  The second is “Windows Explorer,” which is a program which is a component of Windows that provides the desktop, file browser, taskbar and most of the windows that allow us to interact with the PC.  This generated so much confusion that after Win7 Microsoft renamed the O/S component “File Explorer” to more accurately reflect its mission.  Generally, we only see messages about Windows Explorer when it fails to work properly or overloads the system.  This program should only exist in the main Windows directory; if it is found elsewhere, it is usually a Trojan which should be removed.

EXPONENTIAL:  This term is used throughout the definitions in this glossary (i.e. “an exponential increase in zero day exploits”), so let’s define it:  Increasing at a rapidly expanding rate.  To understand this you must be aware that “arithmetic progression” is linear and increases at a constant ratio (such as 1), i.e.  “1,2,3,4,5,”  while exponential (“geometric”) progression is characterized by a constantly increasing rate, since it is compared to its increasing base (the preceding number), such as “1,3,9,27,81”.  So when we say that a virus increases at an exponential rate, it is very rapid indeed.

EXPRESSION:  See StatementA value, constant, variable, operator or function that is in a statement.

EXT2, EXT3:  The Linux file system.  See File System.

EXTENSIBILITY: A software engineering term that defines a system design principle where its implementation takes into consideration future advances and attempts to accommodate them.  It is one step further than “forward compatibility,” which may not completely accommodate all future advances, only allowing some “data” to be used with the newer versions of programs, but not encompassing all of the newer features.  Example: A web development program which can be upgraded to XHTML.  A forward compatible program may display some of the older HTML text in the newer version, but will not be able to take advantage of all of the security and graphics features in the newer version, while an extensible version of the software will be able to handle all of the features.

EXTENSION: a/k/a/ “Filename Extension”.   The (usually three) characters following the dot after a filename description (e.g.  Later versions of programs, Office 2007 and 2010 for example, use four characters (filename.docx), where the additional character stands for XML (Extensible Markup Language), the programming language behind later versions of MS Office. The length of the filename depends on the system on which it is being run.  For example, DOS filenames and earlier Windows filenames are limited to a “base name” containing no more than eight characters plus the three character file extension (the so-called “8.3” format), but later versions of Windows (starting with Windows NT 3.5 in 1994) have increased the file name length to a theoretical maximum of 255 characters, plus the three character extension (so-called LFN or “Long File Names”).  Unix allows 4 character filenames.  The extension refers to the software that was used to create the data (e.g Word = .doc; Word Perfect = .wpd, etc.), which is used to read it after it has been saved.  In order not to reinvent the wheel, here’s a LINK to an excellent site that has a comprehensive list of extensions.  If you really get stumped, later versions of Windows prompt an Internet search if your computer cannot find a program to open the file extension.


EXTRANET:  See, networks.

EXTREME PROGRAMMING:  See AgileA creation of Kent Beck at Chrysler Corp. in the 1990s, which promotes software quality via frequent “releases” in short development cycles.

EYE-FI: A type of SD memory card that fits into a digital camera that not only stores photos and videos like a standard SD or SDHC memory card, but also allows you to specify where, over a wireless network, you want the data sent (to a computer or the Internet).





























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