When most people go to buy a computer these days, they’re confronted with a massive list of options from which to piece together their "dream" system.  The problem is that their "dream" system is one that they don’t have to think about.  Unfortunately, until engineers can find a better way to describe computers, learning a few things about how they’re made can be useful.  Today, I’m going to explain very simply the difference between a computer’s hard drive, and it’s memory (RAM).

Memory -vs- Paper

Your memory is just like a computer’s memory.  It’s fast.  You can recite information much faster when you have it memorized, and a computer can modify documents faster when they’re in it’s memory.

The problem with our memory though is that we sometimes forget things.  A computer’s memory is the same way.  When you close a program it "forgets" anything that it had in it’s memory for that program.  But if you’re typing up a big document, you don’t want to lose all your changes.  We all know what happens if we try and close a program without saving the document.  The computer asks us if we want to save it, or lose our changes. 

Most of the time we click "Save". When we do that, the computer takes what it has in it’s memory, and writes it down on the hard drive.  Just like we’d write something down on paper to save, the computer puts things on the hard drive that it doesn’t want to forget.  It’s not a perfect metaphor but the principle is the same. 

Size

So why are hard drives so many more GB than memory (RAM)?  Let’s think about a filing cabinet filled with old bills.  Do you know the amount of every one of those bills?  Of course not.  But if you needed to know the amount of some bill from two years ago, you could look it up and memorize it.  Your computer doesn’t need to be able to hold all of your documents in it’s memory at the same time, just the one’s that you need to work on at any given moment.  But most of us have lots and lots of documents, music files, pictures, etc…  So the computer needs a big filing cabinet (hard drive) to organize them.

So the next time you’re shopping for a computer hopefully this will help you understand what you’re choosing.

This entry was posted on Friday, November 9th, 2007 at 2:06 pm and is filed under Computers For Dummies. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.