Glossary

Apple is the company that makes Macintosh computers, such as the iMac, Mac mini, MacBook, MacBook Air, MacBook Pro, and Mac Pro. Apple also makes several personal electronic devices, including the iPod, iPhone, and iPad.

While Apple is most known for its hardware devices, the company also develops a wide range of software. Examples include the Mac OS X operating system, iLife, iWork, and several professional media applications, such as Aperture, Logic Studio, and Final Cut Studio.

Apple has also expanded its reach online with the iTunes Store, App Store, and the new Mac App Store. These services allow you to download media and applications directly to your computer. Apple also has over 300 retail stores worldwide, which offer Apple products and provide Apple product support.

This a Java program that can be embedded in a Web page. The difference between a standard Java application and a Java applet is that an applet can't access system resources on the local computer. System files and serial devices (modems, printers, scanners, etc.) cannot be called or used by the applet. This is for security reasons -- nobody wants their system wiped out by a malicious applet on some wacko's Web site. Applets have helped make the Web more dynamic and entertaining and have given a helpful boost to the Java programming language.

An application, or application program, is a software program that runs on your computer. Web browsers, e-mail programs, word processors, games, and utilities are all applications.

The word "application" is used because each program has a specific application for the user. For example, a word processor can help a student create a research paper, while a video game can prevent the student from getting the paper done.

In contrast, system software consists of programs that run in the background, enabling applications to run. These programs include assemblers, compilers, file management tools, and the operating system itself. Applications are said to run on top of the system software, since the system software is made of of "low-level" programs. While system software is automatically installed with the operating system, you can choose which applications you want to install and run on your computer.

Macintosh programs are typically called applications, while Windows programs are often referred to as executable files. This is why Mac programs use the .APP file extension, while Windows programs use the .EXE extension. Though they have different file extensions, Macintosh and Windows programs serve the same purpose and can both be called applications.

An archive contains multiple files and/or folders within a single file. Archives can be saved in several different formats, most of which incorporate file compression to reduce the file size. They are used for consolidating a group of files into a single package. This can be helpful when transferring multiple files to another user or when backing up data.

In order to open the files contained in an archive, they must first be extracted using a file extraction utility. If the archive is compressed, it must be decompressed before the files can be extracted. Most file decompression programs perform both of these operations automatically.

An array is a data structure that contains a group of elements. Typically these elements are all of the same data type, such as an integer or string. Arrays are commonly used in computer programs to organize data so that a related set of values can be easily sorted or searched.

Stands for "American Standard Code for Information Interchange." ASCII is the universal standard for the numerical codes computers use to represent all upper and lower-case letters, numbers, and punctuation. Without ASCII, each type of computer would use a different way of representing letters and numbers, causing major chaos for computer programmers (allowing them even less sleep than they already get).

ASCII makes is possible for text to be represented the same way on a Dell Dimension in Minneapolis, Minnesota as it is on an Apple Power Mac in Paris, France. There are 128 standard ASCII codes, each of which can be represented by a 7 digit binary number (because 2^7 = 128).

A backup is a copy of one or more files created as an alternate in case the original data is lost or becomes unusable. For example, you may save several copies of a research paper on your hard drive as backup files in case you decide to use a previous revision. Better yet, you could save the backups to a USB flash disk, which would also protect the files if the hard drive failed.

Hard drives are meant to run for many years without crashing. But just like all electronic devices, they are not immune to problems. Because they are not solid state devices, hard drives rely on moving parts to access data, which can malfunction and cause your data to become unrecoverable. If you need proof of how fragile hard drives really are, go to your local computer store and have someone show you an open hard drive. When you realize all your data is stored in such a small, delicate device, you may have a new understanding of why you need to backup your data.

But it's not just hardware malfunctions you have to worry about. Software corruption can also damage your files. Directory structures can become damaged and cause entire folders to disappear. Files can be mistakenly deleted or corrupted by viruses or other software attacks. Program installation conflicts can make applications or files unusable. There are unfortunately many ways for your data to become damaged or disappear.

Stands for "Beginner's All-purpose Symbolic Instruction Code." BASIC is a computer programming language that was developed in the mid-1960s to provide a way for students to write simple computer programs. Since then, the language has evolved into a more robust and powerful language and can be used to create advanced programs for today's computer systems.

BASIC originally used numbers at the beginning of each instruction (or line) to tell the computer what order to process the instructions. Lines would be numbered as 10, 20, 30, etc., which would allow additional instructions to be placed between commands later on if needed. "GOTO" statements enabled programs to loop back to earlier instructions during execution. For example, line 230 of a BASIC program may have an "if" clause that tells the computer to jump back to line 50 if a variable is less than 10. This instruction might look something like this:

230 IF (N < 10) THEN GOTO 50

More modern BASIC implementations use "while loops," which perform a series of instructions as long as a certain case is true. Newer BASIC development software also supports more data types, such as integers, strings, and arrays, for storing variables and other data. While the first BASIC development environments were strictly text-based, today's BASIC programming software allows developers to design much of their programs visually, using a graphical user interface. Some of the more popular BASIC development programs used today include REALbasic and Microsoft Visual Basic.

A batch file is a type of script that contains a list of commands. These commands are executed in sequence and can be used to automate processes. For example, some programs may include a batch file that executes a number of commands as the program starts up. A user can also create a custom batch file to automate tedious processes such as copying multiple directories or renaming several files at once.

Batch files are run by the COMMAND.COM program, which is part of DOS and Windows. Therefore, batch files can only be run within the Windows operating system. Macintosh and Unix have other scripting tools, such as AppleScript and Unix shell commands, that can be used for similar tasks. Because batch files contain executable commands, it is important not to open unknown batch files on your hard disk or in e-mail attachments.

File Extensions: .BAT, .CMD

Binary is a two-digit (Base-2) numerical system, which computers use to store data and compute functions. The reason computers use the binary system is because digital switches inside the computer can only be set to either on or off, which are represented by a 1 or 0. Though the binary system consists of only ones and zeros, the two digits can be used to represent any number.

For example:

A single 0 in binary represents zero.
A single 1 represents (2^0) or 1.
10 represents (2^1) or 2.
11 represents (2^1 + 2^0) or 3.
100 represents (2^2) or 4.
101 represents (2^2 + 2^0) or 5.
110 represents (2^2 + 2^1) or 6.
111 represents (2^2 + 2^1 + 2^0) or 7.
1000 represents (2^3) or 8, and so on.