Understanding the Types of Memory

This section outlines different types of computer memory. The term memory refers to anything that stores information either permanently or temporarily. Computers have two different flavors of memory, ROM and RAM.

Remembering the purpose of memory

Before we look at the different types of memory, let's first ensure that you understand the purpose of memory. We can compare memory to your desk at home or in the office. Whether sitting at your home or office desk, chances are your desk is covered with documents, books, and papers. This desk is your work area, and its size dictates how many documents you can work on at any given time.

System memory works the same way. You have documents and applications stored on the hard drive. When you want to work on these documents, you open them and place them in the computer's work area. The work area (or desk space) for a computer is system memory. When you want to work with any application or document, the computer must retrieve that information from the hard drive and execute it from memory.

Assume, for instance, that your computer has 512MB of memory (not a lot in this day and age). You start up your system, which is running Windows XP, and decide to run Microsoft Word and Adobe Photoshop at the same time. Assume that you have opened two very large files in each application. Assume further that you are using 480MB of precious memory at this point - a few MBs for the operating system to load, and a few for each running application. As you can see, your memory usage adds up quickly.

In this scenario, you have already used 480MB of memory, which leaves 32MB of memory remaining. Assume that you are about to open up a Photoshop document and copy and paste information from one file to another. To put it simply, you are running out of desk space. You can solve the problem in one of two ways: You can either do less work (in other words, work on one application at a time - although this solution would not serve business users very well because they often need to run multiple applications simultaneously), or you can get a bigger desk, which in computer terminology means installing more RAM. When you install more RAM, you have a bigger desk to work on. Now that you understand the general purpose of memory, let's dive into the different types of memory. There are many different types of memory you are required to know that are outlined in the next sections.