How to Starting and Stopping Ubuntu

Starting and stopping a computer is a simple process. However, there are good ways to do so and bad ways, too.


Booting
Booting a computer refers to the process of starting it by turning on the power. Rebooting means to restart the computer by telling the operating system to first gracefully stop, and then restart itself. Generally, you shouldn't reboot a computer by turning the power off and then on.


Choosing from the options that stop your computer
There comes a time when all good things must come to an end — even if for a short time. When you stop using your computer, Ubuntu provides several options to save power and protect your data. To access these options, choose System Quit from the GNOME menu bar. Or you can simply click the red Quit button in the upper-right corner of the screen.

Either way, the Quit dialog opens, with these options:

• Shut Down: Gracefully ends all activity and turns the power off.

• Your graphical desktop disappears, and Ubuntu lists the systems that it's shutting down. After Ubuntu finishes shutting down its systems, you're prompted to press the Enter key to finish the process. Press the Enter key, and your computer shuts down and turns itself off.

• Restart: Gracefully ends all activity and then restarts your computer processor and memory and loads Ubuntu. You can use the computer with a clean slate.

• Your computer shuts itself down — stopping all programs, applications, and services, and unmounting (making the file partitions unavailable to Ubuntu) all devices — and then starts itself up.

• Log Out: Closes your desktop and all programs running from it.

• After logging out, Ubuntu continues to run, but you have to log in again to start using it.

• Lock Screen: Prevents anyone who doesn't have your password from unlocking the screen.

• Switch User: You log in as another user using this option but continue to run the applications you were running as the original user. You can log in — switch back — to the previous user login and pick up where you left off.

• Suspend: Remembers your computer's current state, but uses almost no power. Your screen goes blank and you hear your hard drive and fans turn off. The power button on your computer box and monitor flash periodically so you know you're in suspend mode. Pressing a key or moving the mouse wakes the computer in a few seconds.

You can save time and money by making use of the Suspend feature. Suspending puts your computer into a state that requires very little energy; the side benefit is that it's also very quiet.

If your computer loses power while it's suspended, it's just like when you lose power while you're working. The computer reboots, and you lose any work that wasn't saved. If you don't want to risk losing your work while suspended, use the Hibernate option instead.

• Hibernate: Remembers your computer's current state and gracefully shuts down. Your computer doesn't use any power. This option works whether you're running from a live Ubuntu disc or from Ubuntu installed on your hard drive.

When the computer hibernates, it first saves its state (the contents of its memory and the CPU) to its hard drive. Then, unlike suspension, it completely shuts itself off. The CPU doesn't continue to operate in any fashion, nor does the monitor or computer power switch flash periodically.

Hibernation will survive a power outage.

To wake the slumbering beast, you must press the power button. The computer initially looks like it's doing a normal startup: You see the BIOS access instructions display, and then Ubuntu shows its startup sequence.

However, rather than continue through the entire startup process, Ubuntu sees the hibernation state file on the hard drive and reloads it. This process short-circuits and speeds the rest of the boot sequence.

You can program your computer to suspend itself automatically.


To automatically suspend your computer whenever it's unused for a period of time, follow these steps:
1. Click the GNOME Main Menu and choose System Preferences Power Management.

2. The Power Management Preferences dialog opens, with the Put Computer to Sleep when It Is Inactive For slider set to the default, Never.

3. Click the slider and move it to the time after which the computer will go to sleep.
The time can be between one minute and one hour.

4. Click OK.

It's easy to wake up Ubuntu when it's suspended. Follow these steps:

1. Press a key or move the mouse.
You'll hear your computer start to wake up. It should take only 10 to 15 seconds to be back up and running. Many laptops wake up when you open them.

2. Enter your password when prompted.
You're prompted for the password of the user account last in use when the computer was suspended. After you correctly enter the password, you see everything as it was before suspension.

Source of Information : For Dummies Ubuntu Linux For Dummies