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Early Macintosh Desk Accessories

In the operating system for the Apple Macintosh computer, a Desk Accessory (DA) was a piece of software, originally written as a device driver, conforming to a particular programming model. The purpose of this model was to permit very small helper-type applications to be run concurrently with any other application on the system. This provided a small degree of multitasking on a system that initially didn't have any multitasking ability at all. Image File history File links Web_traffic. ... Image File history File links DA_Mac_1. ... Image File history File links DA_Mac_1. ... Mac OS, which stands for Macintosh Operating System, is a range of graphical user interface-based operating systems developed by Apple Computer for their Macintosh computers. ... The Macintosh project started in early 1979 with Jef Raskin, an Apple employee, who envisioned an easy-to-use, low-cost computer for the average consumer. ... Computer software (or simply software) refers to one or more computer programs and data held in the storage of a computer for some purpose. ... In computing, multitasking is a method by which multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is...

Within the OS, the DA was in fact implemented as a special class of driver. It was installed in the driver queue, and given time periodically and co-operatively as a result of the host application calling SystemTask() within its main loop. A DA was permitted to have a user-interface as long as it was confined to one main window. A special appearance of window frame was reserved for the use of DAs so that the user could distinguish it from the windows of the hosting application. A device driver, often called a driver for short, is a computer program that enables another program, typically, an operating system (OS) (e. ... In computing, the main loop (sometimes called the event loop or main event loop) is a common design approach, typically used by applications featuring an event driven graphical user interface. ...

Typical early DAs included the Calculator and Alarm Clock. Third-party DAs such as spelling checkers could be purchased. It was considered hard to write a DA, especially early on when there was little in the way of developer tools. However, since on the early Mac OS drivers did not have any special privileges, writing a DA was, with practice, no more difficult than any other application.

With the advent of System 7, which included a standard co-operative multitasking feature, the need for DAs diminished greatly, and developers were encouraged to develop small applications instead. The system continued to run DAs (and still does up to Mac OS 9.x) for backward compatibility. System 7 (codenamed Big Bang) was a version of Mac OS, the operating system of the Apple Macintosh computer. ... In computing, cooperative multitasking (or non-preemptive multitasking) is a form of multitasking in which multiple tasks execute by voluntarily ceding control to other tasks at programmer-defined points within each task. ... Mac OS 9 was the last version of what has since become known as the classic Macintosh Operating System (Mac OS), introduced by Apple Computer on October 23rd, 1999. ...

Mac OS X v10.4 'Tiger' contains widgets that are similar to desk accessories in purpose in the form of Dashboard. Mac OS X version 10. ... A widget (or control) is a graphical interface component that a computer user interacts with, such as a window or a text box. ... Dashboard returns the concept of Desk Accessories to the Macintosh Dashboard is a layer within the computer operating system Mac OS X, for hosting mini-applications, such as a calculator or clock. ...