Let’s take this week to explain a common misconception about computer hardware. It’s another one of those things that technicians and even some advertisements about computers assume that the consumer already knows, but it’s not often that anyone bothers to explain the difference.

Computers store and retrieve data in different ways. When you power your computer on, it begins to store information temporarily in your computer’s memory or “RAM (random access memory).” If you (or your computer) decide that something is worth preserving, that data is then written to your computer’s hard drive.

RAM is temporary. When your computer loses power, whether intentional or not, the current contents of your RAM are lost. Each time your reboot your computer, the contents of RAM are erased and cleared out for fresh usage.

On the other hand, information that is written to your computer’s hard drive is significantly more permanent, which is good, because nobody wants to re-type their Christmas card list every year. Hard drives store the information until something needs it.

Hard drives aren’t nearly as fast as memory. It’s just like a human. For example, if I asked you what your phone number was, you could rattle it off to me easily because it is stored in your “memory.” If I asked you for the number of the nearest pizza delivery place (where is that, by the way?), you could find the information in the phone book. However, the time it would take you to relay the correct information back to me would be longer because you have to look up the information, then store it in your “memory” before you tell it to me.

Hard drives and RAM work together constantly. When you power on your computer, large chunks of your computer’s operating system are read from the hard drive and stored (temporarily) into RAM. When you access programs, portions of those programs are copied into RAM while they’re in use. When you open a document, that document is loaded into RAM while you’re working on it, then the changes are written back to the hard drive when you click “Save.”

So, what happens when a program requests that something be written into your RAM, but your memory is already full? Your computer won’t (usually) just give up and lock down. Your computer’s operating system is designed to “cheat” a bit. It takes data that is hanging out in RAM and writes it to a special place on the hard drive. Then it uses the place where that data was stored in RAM for the new data that has requested a stay. Unfortunately, this creates a bit of a bottleneck. Now, when the portion of the program that was temporarily written to the hard drive needs to be used, it must be written back into RAM, usually necessitating that something else has to be written temporarily to the hard drive…you get the picture. This is what is called “swapping,” or “paging.” Your computer is swapping information from one form of memory to another. It’s a slow process.

Now you’ll understand why computer guys are always telling you that you need more memory. It’s not that your computer can’t store enough information, it’s because you’re wanting to run more programs at once than your RAM will allow for before getting full and having to “page” to your hard drive. You may have tons of free space on your hard drive, but if you don’t have enough RAM, you’ll quickly see your computer slow to a crawl just when you need it most.

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[Author’s Note: “Ask the Geek” is published weekly in the Stratford Star - the penultimate reading experience for residents of Stratford, Texas, population 1,920. It is posted on WritersCafe.net for posterity. Feel free to comment, but I can’t promise you’ll make the Star.]