CompTIA A+® Certification All-In-One For Dummies®, 2nd Edition

3.1. Understanding the Types of Memory

This section outlines different types of computer memory — anything that stores information either permanently or temporarily. Computers have two different flavors of memory: ROM and RAM.

NOTE

From an exam perspective, make sure you fully understand the different types of memory and their uses because you are sure to see a few questions on memory.

3.1.1. Remembering the purpose of memory

Before you look at the different types of memory, you need to understand the purpose of memory. Think about your desk at home or in the office. Whether sitting at your home or office desk (working on a proposal or preparing for your A+ Certification exam), chances are good that 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 ...