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

memory

Internal storage areas in the computer. 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
    DID YOU KNOW?
    Internet of Things Shaping IT's Future

    To make the IoT both work and pay off, IT is juggling upgrading and building app-centric networks, mapping out new data center architectures and... Read More »

    What You Don't Read Can Hurt You

    Does this sound familiar? An online service promises to help your small business cut costs, increase productivity, make your coffee and walk your... Read More »

    Who's Moving Ahead in Cloud Computing?

    The future remains, well, cloudy. But either way: Amazon, look out. Microsoft is gaining fast. Read More »

    QUICK REFERENCE
    Webopedia Polls

    The trend for the past two years has been for shoppers to spend more online during the holiday season. How do you typically shop for holiday... Read More »

    How to Create a Desktop Shortcut to a Website

    This Webopedia guide will show you how to create a desktop shortcut to a website using Firefox, Chrome or Internet Explorer (IE). Read More »

    Flash Data Storage Vendor Trends

    Although it is almost impossible to keep up with the pace of ongoing product releases, here are three recent highlights in the flash data storage... Read More »