[Mac OS X] What's 'System Events'?

不知道从什么时候起, 我的 Login Items 里面多了个 System Events, 这是个什么东东? 肯定会增加系统负担, 不管三七二十一, 先 stop 掉再说!

刚 search 一下, 在 apple 的网站上找到些线索:

System Events and GUI Scripting

System Events is a faceless application that supplies the terminology for using a number of features in AppleScript scripts. Among these features is GUI scripting, which allows your scripts to perform some actions in applications that have no built-in scripting support. System Events, which is located in /System/Library/CoreServices, has been part of Mac OS X since version 10.1 (Puma), though its features have evolved since that release.

The following are some of the terminology suites supplied by System Events in Mac OS X version 10.4. For more information, display the application dictionary, as described in “Script Editor.” You can also get information on many of the features supported by System Events in Mac Help (from the Help menu in Mac OS X) and at the AppleScript GUI Scripting web page at the AppleScript in Mac OS X website.

• Disk-Folder-File suite

  Provides terminology to access disks, files, and folders without targeting the Finder. This can be more efficient than using the Finder, and can prevent certain kinds of conflicts.

• Folder Actions suite

  Starting with AppleScript 1.9.0 in Mac OS version 10.2, System Events supports the Folder Actions feature, described in “Folder Actions Setup.”

  If you enable Folder Actions, the System Events application is always active. Otherwise, it is only active when a script targets it.

• Power suite

  Provides commands for sleeping, logging out, shutting down, or restarting your computer.

• Property List suite

  Provides terminology for working with information in property list files.

• Processes suite

  Provides classes and commands for GUI Scripting, a feature available starting in Mac OS X version 10.3 that allows scripters to control applications that are either not scriptable or only partially scriptable. With GUI Scripting, AppleScript scripts can select menu items, push buttons, and perform other tasks to control the interfaces of most non-Classic applications. However, as the name implies, GUI scripting works by scripting the user interface, and so tends to result in fragile scripts. For example, items in an application’s user interface may change in various ways between releases, or even between launches of the application, depending on preference settings and other factors.

  This suite is called the Processes suite because in GUI scripting, the root for any script must be a process (represented by an instance of the application process class). The GUI Scripting architecture is based on the accessibility support in Mac OS X, which must be enabled, in Mac OS X v10.4, through the AppleScript Utility. Prior to Mac OS X v10.4, GUI scripting was enabled through the “Enable access for assistive devices” checkbox in the Universal Access preference pane in System Preferences.

  For more information, see the GUI Scripting web page.

• System Events suite

  This suite provides a great deal of terminology for working with parts of the OS. That includes properties for accessing certain folders (preferences folder, favorites folder, desktop pictures folder, and so on), the startup disk, and other useful items.

• XML suite

  Provides terminology for working with information in XML files.

• Accounts suite and Login Items suite

  System Events supports scripting of the System Preferences Accounts pane through the terminology in these two suites.

想起来了, 我以前在一个目录上启用了 Folder Actions, 就是它需要 System Events, 看来还得把它 start 起来.