5/3/2023 0 Comments Facebook friends list order![]() Some assistive technology and other accessibility features come bundled with all operating systems, but typically these applications provide only a minimal level of accessibility, not the full set of features that many users require for equal access to the OS and its applications. For example, the lone developer of a screen-reading product for Mac OS discontinued development of this product, as well as its screen magnification product, as of Mac OS 9.x. Despite these efforts, however, there still are comparatively few assistive technology products available for Mac OS. Also, Apple has now built accessibility into its Carbon application programming interface (API), which allows Mac OS X applications to more effectively communicate with assistive technologies. For example, it is now possible to access much more of the OS interface via keyboard than had been possible in previous versions. With the release of Mac OS X, Apple improved the accessibility of its operating system. (For more information, see the AccessIT Knowledge Base article What is MSAA?) These early efforts to support accessibility, combined with the market dominance of Windows, led to a disproportionate number of assistive technologies being developed for Windows. ![]() This standard, called Microsoft Active Accessibility (MSAA), has been available since Windows 95. Microsoft also developed a standard by which applications could effectively communicate with assistive technologies. Other graphic operating systems have failed to deliver comparable accessibility, particularly for nonmousing and/or nonvisual users. Most Windows applications, for example, are entirely operable via keyboard (i.e., a mouse isn't required). Microsoft addressed many of the accessibility problems of its Windows API fairly early on and provided developers with the tools to develop applications that were accessible. To date, there has been a significant disparity in the accessibility of operating systems' APIs. As long as the API provides the means for delivering these and other accessibility features, applications within that environment can easily be made accessible by software application developers. For example, all menus and controls in a graphic user interface should be accessible via keyboard, not just mouse, and should be displayed with a font and color scheme that can easily be customized by the user. It is important that the API provide support for accessibility. The API provides a set of building blocks, which programmers assemble into an application. All programs developed using a common API will have a similar interface, which makes applications easier to learn and use. One role of the graphic operating system is to provide an application program interface (API) to programmers so they can write applications consistent with the operating environment. However, a variety of graphic desktop environments have been developed for these operating systems and, consequently, have erected barriers for nonmousers and nonsighted users. The latter two operating systems both have strong command-based traditions that linger today, and assistive technologies that support their command-line interfaces have long been available. UNIX and Linux (an open-source UNIX-like operating system) are also widely used, particularly in higher education. In education, the most common graphic operating systems today are Microsoft's Windows and Apple's Mac OS. However, as operating systems became increasingly graphics-oriented, accessibility barriers increased for individuals who couldn't see the graphics or use a mouse. Early operating systems, including Microsoft's Disk Operating System (DOS) and UNIX (originally developed by Bell Labs now an open specification licensed by The Open Group), posed few accessibility barriers for users of assistive technologies because they were text-based. The OS provides a software platform on top of which application programs can run. On any computer, the operating system (OS) is the set of programs that performs basic tasks that are necessary for the computer to be functional.
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