CS101 Definitions Modules 109-145

mportant definitions of CS 101 from Module 109 to Module · 145. · API

Application programming interface is a series of functions that programs can use to make the operating system do their work. Using Windows APIs, for example, a program can open windows, files, and message boxes as well as perform more complicated tasks by passing a single instruction. Windows has several classes of APIs that deal with telephony, messaging, and other issues.

ASCII

American Standard Code for Information Interchange Bland, unformatted text files are best saved in ASCII (pronounced "askee") format. But ASCII is more than a text file format. It's a standard developed by the American National Standards Institute (ANSI) to define how computers write and read characters. The ASCII set of 128 characters includes letters, numbers, punctuation, and control codes (such as a character that marks the end of a line). Each letter or other character is represented by a number: an uppercase A, for example, is the number 65, and a lowercase z is the number 122. Most operating systems use the ASCII standard, except for Windows NT, which uses the suitably larger and newer Unicode standard.

Beta software

Beta versions of commercial software are work-in-progress test copies released prior to the full version. They're used to put the product through real-world tests and to ferret out bugs before the finished software hits the shelves. Betas often expire after a period of time, usually when the full version or the next beta is released. Originally, beta software was released only to developers, but increasingly betas are offered to the general public, usually through the manufacturer's Web site. Testing beta software can be a great way to try out a new product that you're not sure you want to buy. But be warned: if you decide to experiment with betas, expect an occasional software glitch or system crash.

Binary

A numeric system that represents all numbers using only two digits: 1 and 0. Binary is used by computers because each binary digit can be represented by a single digital switch set to either on or off. Each of these digital switches is called a bit. An 8-bit computer processor represents data using sets of 8-bits, a 16-bit processor uses 16 bits, and so on. The more bits a computer can process at once, the larger the numbers it can work with.

Bitwise operators

JavaScript bitwise operators (&, |, ^, ~, <<, >>, >>>) work on numbers, just like arithmetic operators (+, -, /, *) do. But whereas arithmetic operators work on the actual values of

I

numbers, bitwise operators work on their binary representations. Bitwise operators treat their operands as a set of bits (zeros and ones) rather than as decimal, hexadecimal, or octal numbers. Although the operators act upon binary representations of the operands, they return standard JavaScript numerical values.

BIOS

The BIOS is what's coded into a PC's ROM to provide the basic instructions for controlling system hardware. The operating system and application programs both directly access BIOS routines to provide better compatibility for such functions as screen display. Some makers of add-in boards such as graphics accelerator cards provide their own BIOS modules that work in conjunction with (or replace) the BIOS on the system's motherboard.

Bit

Binary digit A bit is the smallest unit of data in computing, with a value of either 0 or 1. Whenever you see a lowercase b associated with a number, it's likely to be a bit.

Boolean

English mathematician George Boole (1815-64) founded a field of mathematical and philosophical study called symbolic logic. His name is now used most often to describe a subset of symbolic logic: constructing database queries. The most common Boolean operators are AND (you're looking for all terms), OR (you're looking for at least one of the terms), and NOT (you're excluding a term).

Boolean operator

This is one of a number of conjunctions (AND, OR, NOT, and less commonly WITH or ADJ) used in constructing Boolean queries.

Browser

A browser is your interface to the World Wide Web; it interprets hypertext links and lets you view sites and navigate from one Internet node to another. Among the companies that produce browsers are NCSA Mosaic, Netscape, and Microsoft, as well as commercial services like CompuServe, Prodigy, and America Online.

Bus

In broadest terms, a bus is a common connection between electrical devices. In computers, bus most commonly means the data pathway that connects a processor to memory and to other "peripheral" buses, such as VESA and PCI.

Byte

A byte usually denotes 8 bits (also called an octet or a word), which the computer treats as a single unit. Longer sequences like 16 and 32 bits are also possible, abbreviated as uppercase B.

Byte codes

A Java compiler creates platform-independent byte-codes that run inside of a Java Virtual Machine (VM). That means that a Java applet can execute on any machine that supports a Java VM.

COBOL

Common business-oriented language developed in 1960 by a team led by the National Bureau of Standards (now the National Institute of Standards and Technology, or NIST), COBOL was the first standardized business computer programming language. In fact, that's what COBOL stands for: common business-oriented language. Since COBOL was intended for business use, many functions, such as payroll and accounting, are still executed using programs written in the language

.com

1. A file extension used for PC programs, especially those that run under DOS (for
2. A domain type used for Internet locations that are part of a business or commercial enterprise (for example,

Database

A database can be as simple as a shopping list or as complex as a collection of thousands of sounds, graphics, and related text files. Database software is designed to help users organize such information. While early "flat" databases were limited to simple, searchable rows and columns, modern relational databases allow users to access and reorganize data in a variety of ways.

Digital Certificate

Citing concerns about security, many people are still wary of online transactions. In an attempt to lessen those fears, software vendors, security specialists, and online vendors have developed the concept of digital certificates. A digital certificate is a password-protected file that includes a variety of information: the name and email address of the certificate holder, an encryption key that can be used to verify the digital signature of the holder, the name of the company issuing the certificate, and the period during which the certificate is valid. Certificate authorities (CAs) gather information about a person or company and then issue certificates. These certificates can be used as online identification, much in the same way a driver's license can verify your identity in the physical world. If an email message or order form comes through with an attached digital certificate, the recipient can be more confident that the document is genuine. Several technologies (including SET, SSL, and Authenticode) are currently competing for market share, each hoping to become the certificate of choice. See also: encryption