If the user chooses only to log out, as opposed to shutting down or restarting, the user’s loginwindow and launchd processes quit, the system launchd process restarts a new loginwindow process owned by the root user, and the login screen appears. Finally, the user’s loginwindow process closes the user’s graphical interface session, runs any logout scripts, and records the logout to the main system.log file. If all the user’s applications successfully quit, the user’s loginwindow process then forcibly quits any background user processes. If the application fails to reply or quit itself, the logout process is stopped and loginwindow displays an error message. A great example is the Print dialog, which when left open, prevents the application from quitting. ![]() Further, even applications that support Auto Save and Resume may still be waiting for the user if certain dialogs are left open. Applications that do not support these features still respond to the Quit event, but they are programmed to ask the user if changes should be saved. Applications that support the OS X new Auto Save and Resume features can immediately save changes to any open documents and quit. Once the user authorizes the logout, the user’s loginwindow process issues a Quit Application Apple event to all applications. When the currently logged-in user chooses to log out, the user’s loginwindow process manages all logout functions with help from the user’s launchd process. Users can log out any time they want to end their user session, but they also have to log out to shut down or restart the Mac. You can find out more about Power Nap and any required updates from Apple Support article, HT5394, “OS X: About Power Nap.” Logout Some Mac systems require firmware updates to support Power Nap. If FileVault 2 is enabled, the safe sleep-wake process is preceded by the FileVault 2 authentication unlock screen. It should take only a few moments to reload system memory, and the kernel resumes all processes and applications. The booter process indicates that the Mac is restarting from safe sleep mode by showing a light gray version of your Mac screen as it appeared when sleep was initiated and a small progress bar at the bottom of the main display. When you restart a Mac from safe sleep mode, the booter process reloads the saved memory image from the system volume instead of proceeding with the normal startup process. In other words, you can only restart a Mac in safe sleep mode by pressing the power button. Hence the term “safe sleep.”Ī Mac in safe sleep mode must be restarted just like a Mac that was shut down. ![]() This way, if a portable Mac computer stays in sleep mode long enough to completely drain the battery, no data is lost when the system has to fully shut down. When these Mac systems go to sleep, they also copy the entire contents of system memory to an image file on the system volume. Safe Sleep and Standby ModesĪll OS X Mavericks–compatible portable Mac computers support safe sleep, and newer Mac computers with flash storage also support an automatic standby mode. Waking your Mac from sleep mode restarts all hardware, and the kernel resumes all processes and applications from the point at which you left them. This greatly reduces the amount of power used as an example, newer portable Mac devices can remain in sleep mode for up to a month on a single battery charge. Instead, the system kernel pauses all processes and then essentially shuts down all the hardware. The Mac sleep function is convenient because it does not quit any active processes or applications. Many of these settings can be managed remotely from Apple Remote Desktop or from a management server. You can put the system to sleep after a period of inactivity with settings in Energy Saver preferences set a schedule to sleep, shut down, or start up the Mac with settings in the Schedule dialog of Energy Saver preferences automatically log out users after a period of inactivity with settings in Security & Privacy preferences and automatically log out managed users with settings in Parental Controls preferences. For instance, the Installer and Mac App Store applications can request a restart when the installation of new or updated software requires it.įurther, you can configure the Mac to automatically perform certain commands. However, other processes and applications can also initiate sleep, logout, or shutdown commands. This feature works in conjunction with the application Auto Save, as covered in Lesson 20, “Document Management.” Upon login the user’s items reopen to their previous state. ![]() OS X features an automatic Resume feature, enabled by default for all users.
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