Barrons Publishing Dictionary of Computer and Internet Terms 10th

.net suffix indicating that an E-MAIL address or WEB SITE is located at a network with a particular name. Names ending in .net were intended to designate sites that provide Internet connectivity to other networks, but in recent years .net has been used indiscriminately as an alternative to .com.

.NET see .NET FRAMEWORK.

.NET Framework an application program interface (API) for Microsoft Windows, introduced in 2001 as a downloadable add-on to Windows 2000 and XP and included in subsequent versions of Windows.

The purpose of the .NET Framework is to reduce the amount of work programmers have to do, while at the same time increasing reliability and introducing Java-like portability. Despite the name, networking is not its main purpose, although networking is included.

The .NET Framework is fully object-oriented. Programmers communicate with the operating system with a rich system of data types rather than with pointers. For example, if a particular operation requires a list of strings, the programmer can give it a list of strings, rather than a pointer to a place where a carefully constructed list of strings has been stored. The called procedure can verify that a list of strings is indeed what it received. Thus, a very tedious and error-prone task is eliminated.

The .NET Framework manages the memory used by each program. Uninitialized variables and uninitialized pointers—a common source of erratic behavior in earlier software—are generally ruled out. So are “resource leaks” (memory or other system resources allocated to a program and never released when the program ends). The software components used by each program are tightly tied together so that none of them will be replaced accidentally (see ASSEMBLY; contrast DLL HELL).

Like Java, the .NET Framework normally compiles programs into bytecode, a concise notation that is converted to machine language when the program is ready to run.

net neutrality a proposed regulation that would require all ISPs (Internet service providers) to treat all Internet traffic the same. This proposal would prevent ISPs from offering higher speed, higher cost service for certain high-volume traffic such as video downloads. Supporters of this proposal argue that the Internet has traditionally been open equally to all types of traffic. Opponents argue that the proposal would prevent ISPs from investing in enough Internet capacity because they would not be able to raise additional revenue from heavy users.

Comcast had started reducing the transfer speed for some large files downloaded over the Internet, but the FCC ordered them to stop doing this in 2008. The debate continues as this book is published.

net surfing see SURFING.

Net, the a colloquial name for the INTERNET.

NetBEUI (NetBIOS Extended User Interface) a data transmission protocol developed by IBM and Microsoft and widely used in local-area networking. It is usually the preferred protocol for networking Windows

systems but does not support routing. See PROTOCOL; ROUTER. Contrast

ATM; IPX/SPX; TCP/IP.

NetBIOS (Network Basic Input-Output System) an operating system extension designed by IBM to allow software to access a network. NetBIOS includes a network protocol that was later extended to form NetBEUI. See NETBEUI; PROTOCOL.

netcafe an INTERNET CAFE.

netcam a camera attached to a computer, used to send images over a network. Compare WEBCAM. Physically, webcams and netcams are alike; the difference is in how they are used.

netiquette (network etiquette) the conventional practices that make the INTERNET usable. More than just politeness, netiquette involves fundamental respect for the rights of other users who are helping pay the cost of running the network.

For example, it is unacceptable to post off-topic material in NEWSGROUPS, be rude during chats, ask people to do your homework for you, or bother them with commercial solicitations. See also ACCEPTABLE-USE POLICY; COMPUTER ETHICS; NEWSGROUPS.

netizen (Internet citizen) a person who is part of the Internet community in

CYBERSPACE.

Netscape Navigator a pioneering WEB BROWSER, produced by Netscape Communications Corporation (see their web site at netscape.aol.com). In 1998 Netscape was acquired by AOL.

network a set of computers connected together. See INTERNET; INTRANET; LOCAL-AREA NETWORK; WIDE-AREA NETWORK.

network address translation (NAT) the automatic changing of IP addresses by a router or gateway so that several computers can share a single IP address visible to the outside world. This is commonly done in home networks, where the DSL or cable modem has a single IP address. This is a solution to the problem that only about 3 billion IPv4 addresses exist, which is not enough for all the computers in the world.

The router changes the IP addresses on the data packets as they come in and go out so that each computer can communicate with the Internet. By varying port numbers, it ensures that incoming packets can be matched up with the computers for which they are intended. See also PIX.

network attached storage file storage that resides on a separate computer, which owns and manages the files. See FILE SHARING. Contrast DISK SHARING; STORAGE AREA NETWORK.

Network Solutions, Inc. the organization that, until 1998, had sole responsibility for maintaining the registry of top-level domain names (TLDs) ending in .com, .net, and .org, under a contract with the United States Government. Its web address is www.networksolutions.com.

Since 1998, Network Solutions is one of several competing domain name registrars. This process is supervised by ICANN. See also DOMAIN NAME HOARDING; DOMAIN NAME POACHING.

neural network a computer program that models the way nerve cells (neurons) are connected together in the human brain. Neural networks enable a computer to train itself to recognize patterns in a strikingly human-like way. Like the human brain, neural networks give only approximate results, but they can do things that no other kind of computer program can do efficiently.

Figure 177 shows how a neural network is set up. Each neuron has several inputs but only one output. Some of the inputs excite (activate) the neuron while others inhibit it, each with a particular strength. The idea is that each output neuron will be activated when one particular kind of pattern is present at the input. In the computer, the neurons and connections are simulated by arrays of numbers.

FIGURE 177. Neural network

Training a neural network is like training an animal. Patterns are applied to the input, and a simple algorithm adjusts the weights of the connections to try to get the desired output. After many training runs in which many different patterns are utilized, the neural network “learns” to recognize patterns of a certain kind. Even the programmer need not know exactly what these patterns have in common, because the patterns are analyzed by the neural network itself.

Neural networks are good at recognizing inputs that are vague, illdefined, or likely to contain scattered variation. For example, a neural

network can recognize images of human faces, or patterns of weather data, or trends in stock market behavior. However, a neural network is never 100% reliable, and even simple calculations can be quite slow.

new the command in C++, C#, and Java that calls the CONSTRUCTOR for a class to create a new object of that class. See

PROGRAMMING.

new media the means of communication that are displacing newspapers and television at the beginning of the 21st century. Chief among them is the World Wide Web or, more generally, the Internet. Some differences between the Web and earlier media include the following:

•Lack of central control. Almost anyone can publish almost anything without an editor’s or publisher’s approval.

•Audience participation. Readers of new media often have the ability to communicate with the producers and often post comments for other readers to see.

•Very low cost of production. You do not have to own a TV station or newspaper company to express yourself; everyone has a voice. In the 1500s, the printing press had a similar impact. It allowed any educated and reasonably prosperous person to print handbills and give them out. Later, newspapers and magazines arose as means of mass communication through printing.

•Computer-assisted access. Computers can help you find material you are interested in and filter out things you do not want to see. (See SEARCH ENGINE.)

•Multimedia. New media can combine the effects of print, painting, photography, music, motion pictures, and animation while adding new capabilities of their own, such as hypertext. See HYPERTEXT.

•Volatility. The contents of a web page can be changed at any time; it is possible to rewrite history and deny what you published a few weeks earlier. Libraries need to address this by archiving the World Wide Web for the public good. See WAYBACK MACHINE.

One thing everyone agrees on is that the new media are in their infancy and their most common uses fifty years hence will probably involve techniques that have not yet been invented or foreseen.

newbie (slang) newcomer (to the Internet, a newsgroup, etc.).

newsfeed a link on a web page that is automatically updated with current information. See RSS.

newsgroup a public forum or discussion area on a computer network. All users of the network can post messages, and every user can read all the messages that have been posted. The most famous newsgroups are those distributed worldwide by the Usenet system, covering thousands of topics. See USENET.

newspaper columns a word processor mode that specifies a newspaperlike format with text flowing from one column into the next. Contrast

PARALLEL COLUMNS.

FIGURE 178. Newspaper columns

newsreader a piece of software that enables the user to read Usenet newsgroups. See NEWSGROUP.

NFS (Network File System) a FILE SHARING protocol originally developed by Sun Microsystems in the mid-1980s and now widely used on UNIXbased systems. Compare CIFS.

NIB (describing items for sale) “new, in box.”

nibble a group of 4 bits, or half of 1 byte.

NIC (Network Interface Card) the circuit board inside a computer that connects it to a local-area network.

nicad, NiCd (nickel-cadmium) a type of rechargeable battery formerly used in laptop computers. Nickel-cadmium batteries are toxic and should not be discarded in ordinary trash. See also LI-ION; NIMH; ROHS.

Nigerian scam see 419 SCAM.

NiMH (Nickel-Metal Hydride) a type of rechargeable battery electrically similar to nickel-cadmium (NICAD) but having greater capacity. See also

LI-ION.

nm see NANOMETER.

node

1.an individual computer (or occasionally another type of machine) in a network.

2.a connection point in a data structure such as a linked list or tree.

3.(draw programs) a point on a curve or line that helps define the shape of the line. See CUSP NODE; SMOOTH NODE; SPLINE.

non-breaking hyphen a hyphen that does not indicate a place where a word can be broken apart. For instance, if the hyphenated word “flipflop” falls at the end of the line, then “flip-” can appear on one line, with “flop” at the beginning of the next. But if you type “flip-flop” with a required hyphen, it will not be split up. In Microsoft Word, to type a nonbreaking hyphen press Ctrl-Shift and the hyphen key together.

non-breaking space a space that does not denote a place where words can be split apart at the end of a line. For instance, you might not want a person’s initials (as in “T. S. Eliot”) to be split at the end of a line. You should

therefore use required spaces between them rather than ordinary spaces. In TEX, a required space is typed as ~ (TILDE). In Microsoft Word, a nonbreaking space is typed by pressing Ctrl-Shift and the space bar together.

non-volatile not erased when turned off. Disks are a non-volatile storage medium; memory (RAM) is volatile.

nondocument mode a type of word processing that produces plain-text (ASCII) files with no special codes for hyphenation, page breaks, fonts, or the like. The most common way of saving a file in nondocument mode is to use the “Save as” menu and choose “text file” or “text only.” See

TEXT FILE.

NOR gate (Figure 179) a logic gate whose output is 0 when either or both of the two inputs is 1, thus:

A NOR gate is equivalent to an OR gate followed by a NOT gate. NOR gates are important because all the other types of logic circuits can be built from them. See

FIGURE 179. NOR gate (logic symbol)

Norton Utilities a set of programs originally written by Peter Norton and now a product of Symantec Corporation, used to provide security, recover erased files, and correct other problems with disks. See RECOVERING ERASED FILES. Web address: www.symantec.com/norton.

NOS

1.(Network Operating System) any special operating system or operating system extension that supports networking.

2.(New Old Stock) old but never sold to a customer and still in original packaging; this describes parts for obsolete equipment or the like.

Compare LNIB.

NOT gate (Figure 180) a logic gate whose output is 1 if the input is 0, and vice versa, thus:

Inputs Output

01

10

A NOT gate is also called an inverter because it reverses the value of its input. See

FIGURE 180. NOT gate (inverter)

notebook a computer about the same size as a looseleaf notebook, weighing less than 6 pounds (2.7 kg).

Usage note: The distinction between “laptop” and “notebook” has become blurred; all present-day laptop computers are notebooks by the standards of a few years ago. Many people use “laptop” and “notebook” interchangeably.

NP-complete problem see LIMITS OF COMPUTER POWER.

NPC non-player character, a (simulated) person in an online game who is not controlled by a player.

NPN one of the two types of bipolar TRANSISTORs (contrast PNP).

NRFB (describing items for sale) “never removed from box.” See also

EBAY; MIB.

NSFW Not Safe For Work, a warning sometimes given on an online forum when the upcoming content isn’t appropriate for a work environment.

NSI see NETWORK SOLUTIONS, INC.

NT short for Windows NT. See WINDOWS (MICROSOFT).

NTFS the file system used by Windows NT and its successors. Contrast

CDFS; FAT; WINDOWS (MICROSOFT).

NTSC (National Television System Committee) the type of analog color TV signal used in the United States. It was designed to be compatible with a pre-existing black-and-white system. The screen consists of 525 lines, interlaced, and a complete scan takes 1/30 second. Color information is modulated on a 3.58-MHz subcarrier. Regulations mandated the end of NTSC broadcasting in February 2009, but NTSC video signals will continue to be used in low-cost analog video monitors and the like.

Contrast DIGITAL TELEVISION; HDTV; PAL; SECAM.

.nu suffix indicating that an e-mail or web address is registered on Niue Island in the South Pacific. Niue Island has resold most of its domain addresses for use elsewhere. See TLD.

nudge to move a selected object in small increments by using the arrow keys instead of the mouse.

null-terminated string a CHARACTER STRING that ends with ASCII code 0. Null-terminated strings are used in the C programming language and in many of the system routines of UNIX and Windows.

Num Lock a key on PC-compatible computers that switches the NUMERIC KEYPAD between two functions: typing numbers or moving the cursor with arrow keys.

number crunching (slang) arithmetical calculation, especially for scientific or engineering purposes.

numeric keypad a separate set of keys at the end of the keyboard, containing the digits 0 to 9 and a decimal point key. The digits are arranged in the same way as they are on an adding machine. If you have to type large quantities of numeric data, a numeric keypad is quicker to use than the number keys on the regular keypad. Some people prefer a keyboard without a numeric keypad because it lets them place the mouse closer to where they sit. See also KEYBOARD.

numerical integration the process of finding the area under a particular curve by dividing the area into many tiny rectangles, adding up the heights of individual rectangles, and then multiplying the sum by their common width. See Figure 181. Numerical integration is a good example of a calculation that is practical to do on a computer but not by hand.

FIGURE 181. Numerical integration

For example, in probability theory it is important to find the area under the bell curve defined by:

This area can be found with the program in Figure 182, which uses a loop to perform a numerical integration. As you might imagine, it would

take a long time to perform this calculation with a calculator, and it would be entirely impractical to do it by hand.

NVIDIA a major manufacturer of graphics processors for personal computers, located in Santa Clara, California (www.nvidia.com). The name appears to be a pun on the Latin invidia “envy” although it is usually defined as n for numeric plus video.

NVRAM (non-volatile random-access memory) the memory in which information about a computer’s configuration is stored; it is either powered by a battery or inherently able to retain data when power is off. Compare

CMOS RAM, which is an older term. See also EEPROM; FLASH MEMORY.

class numerical_integration

{

/* This Java program finds the area under the standard normal probability curve between x=0 and x=b, which is 1.0 in this example */

public static void main(String args[])

{

for (double x=dx; x<b; x+=dx)

{

double y = Math.exp(-x*x/2); a += y;

}

double area=a*dx/p; System.out.println(”Area =” + area);

}

}

FIGURE 182. Numerical integration algorithm