How Cable Modems Work

For millions of people, television brings news, entertainment and educational programs into their homes. Many people get their TV signal from cable television (CATV) because cable TV provides a clearer picture and more channels. (See How Cable TV Works for details.)
Many people who have cable TV can now get a high-speed connection to the Internet from their cable provider. Cable modems compete with technologies like asymmetrical digital subscriber lines (ADSL). If you have ever wondered what the differences between DSL and cable modems are, or if you have ever wondered how a computer network can share a cable with dozens of television channels, then read on. In this article, we'll look at how a cable modem works and see how 100 cable television channels and any Web site out there can flow over a single coaxial cable into your home

How AGP Works

You point, you click; you drag and you drop. Files open and close in separate windows. Movies play, pop-ups pop, and video games fill the screen, immersing you in a world of 3-D graphics. This is the stuff we're used to seeing on our computers
It all started in 1973, when Xerox completed the Alto, the first computer to use a graphical user interface. This innovation forever changed the way the people work with their computers.
Today, every aspect of computing, from creating animation to simple tasks such as word processing and e-mail, uses lots of graphics to create a more intuitive work environment for the user. The hardware to support these graphics is called a graphics card. The way this card connects to your computer is key in your computer's ability to render graphics. In this article, you will learn about AGP, or Accelerated Graphics Port. AGP enables your computer to have a dedicated way to communicate with the graphics card, enhancing both the look and speed of your computer's graphics

How accessDTV Works

The excitement around digital television (DTV) has been growing steadily for several years. If you have been to any of the major electronics stores recently, you have probably noticed shelves filled with digital television sets.
At the same time, television stations have been quietly launching their digital transmitters. The stations and the networks have been outfitting their studios and trucks with the equipment they need to shoot, record and edit with purely digital signals. Almost all prime-time shows and sporting events are now digital.
In most major cities, you can receive digital broadcasts. For example, in San Jose, CA, you can receive about a dozen DTV broadcasts. Even in a relatively small city like Raleigh, NC, you can receive four stations. More than 100 million Americans are able to receive at least one digital broadcast, but far fewer than a million currently do. The main barrier has been the price and complexity of home DTV equipment.
In this article, we will talk about the inexpensive PCI card for your computer that allows you to instantly start experiencing everything that DTV has to offer on your computer monitor.

How BIOS Works

One of the most common uses of Flash memory is for the basic input/output system of your
computer, commonly known as the BIOS (pronounced "bye-ose"). On virtually every computer
available, the BIOS makes sure all the other chips, hard drives, ports and CPU function
together.
Every desktop and laptop computer in common use today contains a microprocessor as its
central processing unit. The microprocessor is the hardware component. To get its work done,
the microprocessor executes a set of instructions known as software (see How Microprocessors
Work for details). You are probably very familiar with two different types of software:
The operating system - The operating system provides a set of services for the applications
running on your computer, and it also provides the fundamental user interface for your
computer. Windows 98 and Linux are examples of operating systems. (See How Operating Systems
Work for lots of details.) The applications - Applications are pieces of software that are programmed to perform
specific tasks. On your computer right now you probably have a browser application, a word
processing application, an e-mail application and so on. You can also buy new applications
and install them. It turns out that the BIOS is the third type of software your computer needs to operate
successfully. In this article, you'll learn all about BIOS -- what it does, how to configure
it and what to do if your BIOS needs updating.

Does adding more RAM to your computer make it faster?

Up to a point, adding RAM (random access memory) will normally cause your computer to feel faster on certain types of operations. RAM is important because of an operating system component called the virtual memory manager (VMM).
When you run a program such as a word processor or an Internet browser, the microprocessor in your computer pulls the executable file off the hard disk and loads it into RAM. In the case of a big program like Microsoft Word or Excel, the EXE consumes about 5 megabytes. The microprocessor also pulls in a number of shared DLLs (dynamic link libraries) -- shared pieces of code used by multiple applications. The DLLs might total 20 or 30 megabytes. Then the microprocessor loads in the data files you want to look at, which might total several megabytes if you are looking at several documents or browsing a page with a lot of graphics. So a normal application needs between 10 and 30 megabytes of RAM space to run. On my machine, at any given time I might have the following applications running:
A word processor A spreadsheet A DOS prompt An e-mail program A drawing program Three or four browser windows A fax program A Telnet session Besides all of those applications, the operating system itself is taking up a good bit of space. Those programs together might need 100 to 150 megabytes of RAM, but my computer only has 64 megabytes of RAM installed. The extra space is created by the virtual memory manager. The VMM looks at RAM and finds sections of RAM that are not currently needed. It puts these sections of RAM in a place called the swap file on the hard disk. For example, even though I have my e-mail program open, I haven't looked at e-mail in the last 45 minutes. So the VMM moves all of the bytes making up the e-mail program's EXE, DLLs and data out to the hard disk. That is called swapping out the program. The next time I click on the e-mail program, the VMM will swap in all of its bytes from the hard disk, and probably swap something else out in the process. Because the hard disk is slow relative to RAM, the act of swapping things in and out causes a noticeable delay.
If you have a very small amount of RAM (say, 16 megabytes), then the VMM is always swapping things in and out to get anything done. In that case, your computer feels like it is crawling. As you add more RAM, you get to a point where you only notice the swapping when you load a new program or change windows. If you were to put 256 megabytes of RAM in your computer, the VMM would have plenty of room and you would never see it swapping anything. That is as fast as things get. If you then added more RAM, it would have no effect.
Some applications (things like Photoshop, many compilers, most film editing and animation packages) need tons of RAM to do their job. If you run them on a machine with too little RAM, they swap constantly and run very slowly. You can get a huge speed boost by adding enough RAM to eliminate the swapping. Programs like these may run 10 to 50 times faster once they have enough RAM!
Here are some interesting links:
How RAM Works
How Virtual Memory Works
Check your virtual memory settings
About the Virtual Memory Manager