How do computers remember things?

Computers didn't always remember things. You used to ask it a single question ("What is 23432.692 divided by 1621.22235?" for example) and it would give you a single answer. Nowadays, we don't so much as our computers questions, but ask them to complete tasks for us. We ask them to help us write a letter, look at a photo, read a web page, etc. When writing a letter for example, you often will begin writing and eventually take a break. What keeps the computer from completely forgetting about your paper in the meantime?

Computers, like people, have two different kinds of memory- long-term and short-term. Short-term memory in people is what helps us remember what we ate for breakfast, or what it is we came into a room to get. (I have problems with that last example sometimes!) For computers, the short-term memory is called RAM (Random Access Memory- don't worry if you forget that in five minutes though, I doubt anyone will be quizzing you on it.) This is where it remembers the changes to your letter before you hit the Save button for example.

The other type of memory is your hard drive. You may remember me briefly mentioning the hard drive in the article "Why do computers hum?". The hard drive is where the long-term storage happens. This is where your letter is stored even after you close the program or even turn the computer off. As many of you may remember, if you had a record playing, and the needle got bumped, it could scratch the record. If the record got scratched it was all but ruined- it never played the same again. Hard drives work similarly, but instead of a physical needle touching and reading grooves on a record, it's called a "play head" and it hovers about a hair's width above the disc reading magnetic imprints. (Stay with me! Don't glaze over quite yet!)

Ever heard of a hard drive "crashing"? Crashing usually refers to the play head actually touching the disc and scratching it. Just like your old vinyl record, if the hard drive gets scratched, it'll never work the same way again.

Practical Tip of the Day:
Because hard drives crash, and because there's usually little or no warning to when they do, most people "back up" their information. Backing up simply means making another copy of your information and putting it in a safe place. You probably already do this with your important documents (titles, birth certificates, etc.). You usually have one copy you keep locked up in a safe spot like a safe, and then a photocopy that you can take to show people if need be.

There are many different ways to back up your information, and there's no best way for everyone. Feel free to either message me or talk to your local computer specialist for help picking the method that best fits your lifestyle.