Basic Computer Thermodynamics

By Stephen Bucaro

That desk in front of you and everything else around you is made up of atoms. An atom consists of electrons orbiting around a nucleus. An atom is increadibly tiny. You could line up 10 million of them inside a millimeter. What if we could scale up an atom so that nucleus was size of a basketball? The orbits of its electrons would then be 15 miles away.

From this you can understand that atoms are almost all empty space. The nucleus of atom is composed of quarks. If you could see a quark or an electron up close, it might appear as a tiny vibrating glow of energy. It turns out this world, which is causing us so many problems and so much stress, is mostly an illusion!

The electrons orbit nucleus at about speed of light. If you could see them, they might appear as a blur. They do not orbit in a plane like pictures in books. They create a shell. Sometimes two or more atoms will share electrons, causing them to link together forming a molecule.

Looking at that desk in front of you again, it looks pretty solid. Actually, unless your desk is floating in deep space where temperature is close to absolute zero, molecules of your desk are vibrating like crazy. Picture molecules bouncing around and smacking into each other like balls on a pool table.

If you have ever played pool, you're very familiar with how when a pool ball hits another pool ball, it transfers it's energy to second pool ball. When heat causes molecules to vibrate, they transfer energy between each other in a similar fashion. This action is called "conduction".

Now picture CPU of a computer cooking away because designer wants to push too much power through a small piece of silicon. If we don't take away that heat as fast as it's created, that CPU will fry!

The problem is usually solved by mounting a heat sink on CPU. Conduction causes heat to move from hot CPU to cooler heat sink. Because air doesn't conduct heat as well as metal, We apply a thin layer of heat sink compound between CPU and heat sink to fill in any gaps.

Feel Free to reprint this article in newsletters and on websites, with resource box included. If you use this article, please send a brief message to let me know where it appeared: kara333@earthlink.net

Word Count = 1,500 Word Wrapped to 60 characters per line URL: http://www.karathecomputertutor.com Author photo: http://www.karathecomputertutor.com Date of copyright: November 2004

All About Computer Viruses by Kara Glover kara333@earthlink.net

Your computer is as slow as molasses. Your mouse freezes every 15 minutes, and that Microsoft Word program just won’t seem to open.

You might have a virus.

Just what exactly is a virus? What kind is in your computer? How did it get there? How is it spreading and wreaking such havoc? And why is it bothering with your computer anyway?

Viruses are pieces of programming code that make copies of themselves, or replicate, inside your computer without asking your explicit written permission to do so. Forget getting your permission down on paper. Viruses don’t bother to seek your permission at all! Very invasive.

In comparison, there are pieces of code that might replicate inside your computer, say something your IT guy thinks you need. But code spreads, perhaps throughout your office network, with your consent (or at least your IT guy’s consent). These types of replicating code are called agents, said Jimmy Kuo, a research fellow with McAfee AVERT, a research arm of anti-virus software-maker McAfee Inc.

In this article, though, we’re not talking about good guys, or agents. We’ll be talking about bad guys, viruses.

A long, long time ago in computer years, like five, most viruses were comprised of a similar breed. They entered your computer perhaps through an email attachment or a floppy disk (remember those?). Then they attached themselves to one of your files, say your Microsoft Word program.

When you opened your Microsoft Word program, virus replicated and attached itself to other files. These could be other random files on your hard drive, files furthest away from your Microsoft Word program, or other files, depending on how virus writer wanted virus to behave.

This virus code could contain hundreds or thousands of instructions. When it replicates it inserts those instructions, into files it infects, said Carey Nachenberg, Chief Architect at Symantec Research Labs, an arm of anti-virus software-maker Symantec. Corp.

Because so many other types of viruses exist now, kind just described is called a classic virus. Classic viruses still exist but they’re not quite as prevalent as they used to be. (Perhaps we could put classic viruses on shelf with Hemingway and Dickens.)

These days, in modern era, viruses are known to spread through vulnerabilities in web browsers, files shared over internet, emails themselves, and computer networks.

As far as web browsers are concerned, Microsoft’s Internet Explorer takes most of heat for spreading viruses because it’s used by more people for web surfing than any other browser.

Nevertheless, “Any web browser potentially has vulnerabilities,” Nachenberg said.

For instance, let’s say you go to a website in IE you have every reason to think is safe, Nachenberg said.

But unfortunately it isn’t. It has virus code hidden in its background that IE isn’t protecting you from. While you’re looking at site, virus is downloaded onto your computer, he said. That’s one way of catching a nasty virus.

During past two years, another prevalent way to catch a virus has been through downloads computer users share with one another, mostly on music sharing sites, Kuo said. On Limewire or Kazaa, for instance, teenagers or other music enthusiasts might think they’re downloading that latest Justin Timberlake song, when in reality they’re downloading a virus straight into their computer. It’s easy for a virus writer to put a download with a virus on one of these sites because everyone’s sharing with everyone else anyway.

Here’s one you might not have thought of. If you use Outlook or Outlook Express to send and receive email, do you have a preview pane below your list of emails that shows contents of email you have highlighted? If so, you may be putting yourself at risk.

Some viruses, though a small percentage according to Nachenberg, are inserted straight into emails themselves.