Welcome to Linux Knowledge Base and Tutorial
"The place where you learn linux"
GetNetWise: You
e One Click Away

 Create an AccountHome | Submit News | Your Account  

Tutorial Menu
Linux Tutorial Home
Table of Contents
Up to --> The Computer Itself

· The Central Processing Unit
· Intel Processors
· AMD
· Alpha Processors
· Mips
· SPARC
· ARM Processors

Glossary
MoreInfo
Man Pages
Linux Topics
Test Your Knowledge

Site Menu
Site Map
FAQ
Copyright Info
Terms of Use
Privacy Info
Disclaimer
WorkBoard
Thanks
Donations
Advertising
Masthead / Impressum
Your Account

Communication
Feedback
Forums
Private Messages
Recommend Us
Surveys

Features
HOWTOs
News
News Archive
Submit News
Topics
User Articles
Web Links

Google
Google


The Web
linux-tutorial.info

Who's Online
There are currently, 212 guest(s) and 5 member(s) that are online.

You are an Anonymous user. You can register for free by clicking here

  
Linux Tutorial - The Computer Itself - The Central Processing Unit
  Cache Memory ---- Intel Processors  


The Central Processing Unit

Sometimes people just don't understand. At first, I thought that they "didn't have a clue," but that was really the problem. They had a clue, but a single clue doesn't solve a crime, nor does it help you run a Linux system. You can easily copy a program from a DOS disk onto an Linux system, particularly if Linux is running on your DOS partition. In all likelihood, the permissions are already set to be executable. So you type in the name of the program and press Enter. Nothing happens, or you get an error about incorrect format. Hmmm. The software manual says that it runs on a 386 or higher (which you have), a VGA monitor (which you have), and at least 2Mb of hard disk space (which you have). Why doesn't it work?

This is a true story. A customer called in saying that the system I was supporting at the time (not Linux) was broken. This customer had a program that worked fine on his DOS PC at home. It, too, was a 386, so there shouldn't be a problem, right? Unfortunately, wrong. Granted, in both cases, the CPU is reading machine instructions and executing them, but in fact, they are the same machine instructions. They have to be. The same also applies to a Linux system.

The problem is comparable to German and English. Although both use (basically) the same alphabet, words (sets of characters) written in German are not understandable by someone reading them as English, and vice versa. Sets of machine instructions that are designed to be interpreted under DOS will not be understood under Linux. (Actually, the problem is a little more complicated, but you get the basic idea.)

Just as your brain has to be told (taught) the difference between German and English, a computer needs to be told the difference between DOS and UNIX programs.

In this section, I will talk about the CPU, the brains of the outfit. It is perfectly reasonable for users and administrators alike to have no understanding of what the CPU does internally. However, a basic knowledge of some of the key issues is important so you can completely understand some of the issues I'll get into elsewhere.

Its like trying to tune-up your car. You don't really need to know how oxygen mixes with gasoline to be able to adjust the carburetor. However, knowing that it happens makes adjusting the carburetor that much easier.

I won't go into detail about the CPUs instruction cycle, that is, how it receives and executes instructions. Though I'm interested in things like that and would love to talk about them, it isn't really necessary to understand what we need to talk about here. Instead, I am going to talk mostly about how the CPU enables the operating system to create a scheme whereby many programs can be in memory simultaneously. These are the concepts of paging and multitasking.

Orignally, the only commercial distributions of Linux available were for Intel processors. RedHat released a version for the Digital Equipment Corporation (DEC) Alpha processor, and others have since followed.

In the next section, I will go into a little depth about the Intel process and how Linux interacts with it. Afterwards, I will talk briefly about the DEC Alpha to give you an idea of what it is about. Because of the number of Intel distributions and Intel-based machines, I won't go into the same depth for the Alpha. The concepts a basically the same, though the names of registers, etc., are different.

 Previous Page
Cache Memory
  Back to Top
Table of Contents
Next Page 
Intel Processors


MoreInfo

Test Your Knowledge

User Comments:


You can only add comments if you are logged in.

Copyright 2002-2009 by James Mohr. Licensed under modified GNU Free Documentation License (Portions of this material originally published by Prentice Hall, Pearson Education, Inc). See here for details. All rights reserved.
  
Show your Support for the Linux Tutorial

Purchase one of the products from our new online shop. For each product you purchase, the Linux Tutorial gets a portion of the proceeds to help keep us going.


Login
Nickname

Password

Security Code
Security Code
Type Security Code


Don't have an account yet? You can create one. As a registered user you have some advantages like theme manager, comments configuration and post comments with your name.

Help if you can!


Amazon Wish List

Did You Know?
You can help in many different ways.


Friends



Tell a Friend About Us

Bookmark and Share



Web site powered by PHP-Nuke

Is this information useful? At the very least you can help by spreading the word to your favorite newsgroups, mailing lists and forums.
All logos and trademarks in this site are property of their respective owner. The comments are property of their posters. Articles are the property of their respective owners. Unless otherwise stated in the body of the article, article content (C) 1994-2013 by James Mohr. All rights reserved. The stylized page/paper, as well as the terms "The Linux Tutorial", "The Linux Server Tutorial", "The Linux Knowledge Base and Tutorial" and "The place where you learn Linux" are service marks of James Mohr. All rights reserved.
The Linux Knowledge Base and Tutorial may contain links to sites on the Internet, which are owned and operated by third parties. The Linux Tutorial is not responsible for the content of any such third-party site. By viewing/utilizing this web site, you have agreed to our disclaimer, terms of use and privacy policy. Use of automated download software ("harvesters") such as wget, httrack, etc. causes the site to quickly exceed its bandwidth limitation and are therefore expressly prohibited. For more details on this, take a look here

PHP-Nuke Copyright © 2004 by Francisco Burzi. This is free software, and you may redistribute it under the GPL. PHP-Nuke comes with absolutely no warranty, for details, see the license.
Page Generation: 0.07 Seconds