Webopedia on Google+Webopedia on TwitterWebopedia on FacebookTech Bytes Blog
Main » TERM » M »

memory

Memory is internal storage areas in the computer system. The term memory identifies data storage that comes in the form of chips, and the word storage is used for memory that exists on tapes or disks. Moreover, the term memory is usually used as a shorthand for physical memory, which refers to the actual chips capable of holding data. Some computers also use virtual memory, which expands physical memory onto a hard disk.

Every computer comes with a certain amount of physical memory, usually referred to as main memory or RAM. You can think of main memory as an array of boxes, each of which can hold a single byte of information. A computer that has 1 megabyte of memory, therefore, can hold about 1 million bytes (or characters) of information.

There are several different types of memory:

  • RAM (random-access memory): This is the same as main memory. When used by itself, the term RAM refers to read and write memory; that is, you can both write data into RAM and read data from RAM. This is in contrast to ROM, which permits you only to read data. Most RAM is volatile, which means that it requires a steady flow of electricity to maintain its contents. As soon as the power is turned off, whatever data was in RAM is lost.
  • ROM (read-only memory): Computers almost always contain a small amount of read-only memory that holds instructions for starting up the computer. Unlike RAM, ROM cannot be written to.
  • PROM (programmable read-only memory): A PROM is a memory chip on which you can store a program. But once the PROM has been used, you cannot wipe it clean and use it to store something else. Like ROMs, PROMs are non-volatile.
  • EPROM (erasable programmable read-only memory): An EPROM is a special type of PROM that can be erased by exposing it to ultraviolet light.
  • EEPROM (electrically erasable programmable read-only memory): An EEPROM is a special type of PROM that can be erased by exposing it to an electrical charge.
  •  

    See "Tips to Fix a Slow Running Computer" in the Quick Reference section of Webopedia.

     







    TECH RESOURCES FROM OUR PARTNERS
    LATEST ARTICLES
    8 Agenda Apps to Help Students Stay Organized

    Webopedia's student apps roundup will help you to better organize your class schedule and stay on top of assignments and homework. Read More »

    List of Free Shorten URL Services

    A URL shortener is a way to make a long Web address shorter. Try this list of free services. Read More »

    Top 10 Tech Terms of 2015

    The most popular Webopedia definitions of 2015. Read More »

    STUDY GUIDES
    Java Basics, Part 1

    Java is a high-level programming language. This guide describes the basics of Java, providing an overview of syntax, variables, data types and... Read More »

    Java Basics, Part 2

    This second Study Guide describes the basics of Java, providing an overview of operators, modifiers and control Structures. Read More »

    The 7 Layers of the OSI Model

    The Open System Interconnection (OSI) model defines a networking framework to implement protocols in seven layers. Use this handy guide to compare... Read More »