C H A P T E R 3

Controls

There are two types of radio buttons. One is a small oval that is empty if it is not selected, or is filled with solid black if it is selected. The oval radio button is labeled to the right with a word or phrase.

The second type of radio button is a small picture with a border (unless the picture itself has a continuous edge). Typically, several of these picture radio buttons are placed next to each other, and the one that is selected is indicated by a thick border. Figure 3-17 shows some regular radio buttons and some picture radio buttons.

Figure 3-17Only one radio button in a cluster can be selected

Regular radio buttons

Not selected

Selected

Picture radio buttons

Selected

Not selected

An application can use radio buttons to control options, such as the order in which to sort information. An application can also use radio buttons to change the attributes of a selected object, such as the style of a view. In contrast, an application should use a text button or a picture button—never use a radio button—to bring up a slip; to confirm, authorize, cancel, or stop an action; or to initiate a process.

Radio Buttons

3-17

Page 110 Page 112
Page 111
Image 111
Apple 2 manual 17Only one radio button in a cluster can be selected
Page 110 Page 112

2 specifications

The Apple II is a defining product in the history of personal computing, first introduced in 1977 by Apple Computer, Inc. Designed by Steve Wozniak, the Apple II was one of the first highly successful mass-produced microcomputer products and played a significant role in bringing personal computers into homes and schools.

One of the Apple II's standout features was its color graphics capability. It was one of the first personal computers to provide color output, thanks to its built-in video interface. The initial model supported a resolution of 280x192 pixels with a palette of 6 colors, which allowed for vibrant visuals that set it apart from contemporaries like the monochrome Altair 8800.

The Apple II was notable for its open architecture. This design allowed users to expand the computer's capabilities easily through a series of expansion slots. Users could add floppy disk drives, additional memory, and various peripheral devices, making the system highly adaptable to individual needs. This encouraged a thriving ecosystem of third-party hardware and software, which contributed to its popularity.

Another significant feature was its use of the 6502 microprocessor. This 8-bit CPU was not only affordable but also powerful for its time, allowing the Apple II to run various applications efficiently. Along with a built-in keyboard and an innovative plastic case that housed its components, the design was user-friendly and appealing.

The Apple II also introduced the concept of “bootable software” through the use of floppy disks. The disk operating system (DOS) allowed users to store and run multiple programs without having to reload software manually, providing a level of convenience that had not been widely available before. Key software like VisiCalc, the first spreadsheet program, helped boost sales, showcasing the Apple II's utility in business and education environments.

The computer was also well-known for its early adoption of BASIC programming language. Apple provided an operating system that supported Applesoft BASIC, which enabled users, including students, to write their programs, further fostering a community of developers.

In summary, the Apple II's color graphics, open architecture, powerful 6502 processor, innovative use of floppy disks, and support for BASIC programming made it a revolutionary product in its time. Its legacy laid the groundwork for future personal computers and established Apple as a leader in the burgeoning tech industry. The Apple II remains an iconic symbol of the early personal computing era, reflecting a generation's transition into a digitally connected world.
Top Page Image Contents