C H A P T E R 3

Controls

Figure 3-18Each checkbox can be on or off

Checkbox off

Checkbox on

You can have one checkbox or as many as you need. Checkboxes are indepen- dent of one another, even when they offer related options. Any number of checkboxes can be on or off at the same time. It’s a good idea to group sets of checkboxes that are related, and to separate the groups from other groups of checkboxes and radio buttons. Each group may have a heading to identify it.

Labeling a checkbox unambiguously can be difficult. The label should imply two clearly opposite states. For example, the Sound preferences slip (Figure 3-18) shows a checkbox labeled “Action sound effects” that controls whether or not sound effects are played for actions. If the checkbox is selected, the action sound effects are played. The clearly opposite state, when the checkbox is not selected, is to not play action sound effects.

Checkboxes are usually capitalized like sentences. However, in some contexts it makes more sense to capitalize them like book titles. Checkbox labels should be all lowercase (except for proper nouns) if the checkboxes are part of a group and each label completes a sentence begun by the label of the group.

If you can’t think of a label for a checkbox that clearly implies its opposite state, you might be better off using radio buttons. With radio buttons, you can use two labels, thereby clarifying the states. It’s sometimes tempting to use a checkbox because one item takes up less space than two. However, the resulting item may be ambiguous and thus difficult to understand.

Sometimes using one checkbox instead of two radio buttons can make users focus more carefully on a choice between two states. One state is clearly labeled, but a user must think to figure out the unlabeled state. While thinking,

Checkboxes

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Apple 2 manual 18Each checkbox can be on or off

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.