What does computer restart means a.cold boot b.worm boot c.shut down d.logging off?

Answer 1

A "hard" or "cold" boot/reboot is when the user utilizes the "hard"-ware to stop and/or restart the computer - by pulling the plug, pushing the power button, etc. A hard boot is called a "cold" boot because the computer is off - and if it's been off, it's probably not been operating for some time, and the hardware has cooled to room temperature. Likewise, a "warm" or "soft" boot/reboot is when you use "soft"-ware to stop and/or restart your computer - for example, pressing the shutdown key combination or allowing automatic software updates restart your computer automatically when they finish installing.

When you shut down your computer, it will power off after it has successfully and safely turned off all vital parts of the software, potentially saved your work, etc. Then it will physically stop power to the entire computer, thus stopping the hardware. Logging off, however, does not physically turn off the computer, or even stop the Operating System - it merely ends all tasks that the logged in user was doing, and kicks everything back to the login screen, where the same or another user can provide their credentials and gain access to perform whatever tasks they wanted to do - all without stopping power to any hardware.