I do awareness meditation. It's important because it trains you to stay in the now. We often spin stories about our past or future and completely overlook life as it really is right now this point and time. Meditation can train you to live your real life and not the fantasy in our heads. How often have you associated your reality with the past which does not exist.
For the defrag, imagine when your hard drive has to search for a file. Many times the hard drive will have to look in separate places for pieces of that one file. Defrag brings them all back together. This allows your computer to run smoother. ( hope I explained it right)