Device Manager 1
CHAPTER 1 Device Manager 1 This chapter describes how your application can use the Device Manager to transfer information into and out of a Macintosh computer. The Device Manager controls the 1 exchange of information between applications and hardware devices. Manager Device This chapter provides a brief introduction to devices and device drivers (the programs that control devices) and then explains how you can use the Device Manager functions to ■ open, close, and exchange information with device drivers ■ write your own device driver that can communicate with the Device Manager ■ provide a user interface for your device driver by making it a Chooser extension or desk accessory. You should read the sections “About the Device Manager” and “Using the Device Manager” if your application needs to use the Device Manager to communicate with a device driver. Applications often communicate with the Device Manager indirectly, by calling functions of other managers (for example, the File Manager) that use the Device Manager. However, sometimes applications must call Device Manager functions directly. The sections “Writing a Device Driver,” “Writing a Chooser-Compatible Device Driver,” and “Writing a Desk Accessory,” provide information you’ll need if you are writing your own device driver. If you writing a device driver, you should understand how memory is organized and allocated in Macintosh computers. See Inside Macintosh: Memory, for this information. You should also be familiar with resources and how the system searches resource files. You can find this information in the chapter “Resource Manager” in Inside Macintosh: More Macintosh Toolbox. If your device driver is to perform background tasks, you’ll need to understand how processes are scheduled.
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