COMPUTER NETWORKING.

Definition - What does Computer Network mean?

A computer network is a group of computer systems and other computing hardware devices that are linked together through communication channels to facilitate communication and resource-sharing among a wide range of users. Networks are commonly categorized based on their characteristics.

 A network is a group of two or more computer systems linked together. There are many types of computernetworks, including:

What is a Local-Area Network (LAN)?

A local-area network (LAN) is a computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings, however, one LAN can be connected to other LANs over any distance via telephone lines and radio waves. Asystem of LANs connected in this way is called a wide-area network (WAN).

Most LANs connect workstations and personal computers. Eachnode (individual computer ) in a LAN has its own CPU with which itexecutes programs, but it also is able to access data and devicesanywhere on the LAN. This means that many users can share expensive devices, such as laser printers, as well as data. Users can also use the LAN to communicate with each other, by sending e-mail or engaging in chat sessions.

LANs are capable of transmitting data at very fast rates, much faster than data can be transmitted over a telephone line; but the distances are limited, and there is also a limit on the number of computers that can be attached to a single LAN.

What is a Wide Area Network (LAN)?

A computer network that spans a relatively large geographical area. Typically, a WAN consists of two or more local-area networks (LANs).

Computers connected to a wide-area network are often connected through public networks, such as the telephone system. They can also be connected through leased lines or satellites. The largest WAN in existence is the Internet.

What is a Campus Area Network (LAN)?

Acronym for campus-area network. An interconnection of local-area networks within a limited geographical space, such as a school campus or a military base.

What is a Metropolitan Area Network (LAN)?

Short for Metropolitan Area Network, a data network designed for a town or city. In terms of geographic breadth, MANs are larger thanlocal-area networks (LANs), but smaller than wide-area networks (WANs). MANs are usually characterized by very high-speed connections using fiber optical cable or other digital media.

What is a Home Area Network (LAN)?

Short for home area network. A HAN is a network contained within a user's home that connects a person's digital devices, from multiple computers and their peripheral devices to telephones, VCRs, televisions, video games, home security systems, "smart" appliances, fax machines and other digital devices that are wired into the network.

Testing my computer motherboard and CPU for failures?

A bad computer motherboard or CPU can cause an assortment of different issues on your computer. Below are just a few of the possible issues you may encounter. It is important to remember that the issues below can also be caused by more than just a bad motherboard and CPU.

1. Computer does not boot, instead you get a beep code. See the POST and beep code page for additional information about beep codes.
2. Random computer crashes causing General Protection Fault error messages, Illegal Operations, Fatal Exceptions, etc.
3. Computer randomly reboots.

There are several different ways to test your computer's motherboard and CPU to determine if it's bad or has flaws that are causing issues with your computer. Below is a listing of these recommendations.

Software and Hardware solutions

Below is a listing of a software programs available that are designed to test your computer's motherboard and CPU. However, with the complexity and wide variety of computer motherboards and CPUs, these programs may not detect every possible failure.

• Hot CPU Tester - Our software recommendation for testing a computers motherboard and CPU. This is a great tool.  Easy to run and use for looking for failures with your computer. In addition to testing a computer, this program also includes a burn-in feature for new computers or computers with a new motherboard or CPU.

In addition to the above solutions, there are other fantastic 100% commercial products. Below is a listing of some of these products.

• PC-doctor - A fantastic but not cheap solution often used for service centers and technicians to diagnose computer hardware issues including motherboard issues.
• PC Diagnostics - Another company that offers both hardware and software solutions for testing the majority of the hardware in your computer including the motherboard.
• Ultra-X - Another great collection of products that can help test computer hardware including the motherboard.

Replace the motherboard and CPU

If the motherboard or CPU is bad after trying the above suggestions, we suggest replacing it.

Troubleshooting a bad video card

Note: This page is for troubleshooting a bad video card, before following the steps below we suggest you go through the no display troubleshooting steps. No display can be a monitor related issue, not a post issue, or a video card related issue.

Caution: Each of the steps will require that you open and work inside your computer. While inside the computer make sure you're aware of the potential ESD dangers.

Reseat the video card

If your video card is not an on-board video card, verify that your video card is not loose by removing the video card from the computer and then re-inserting the video card back into the same slot it was removed.

Exchange video

If reseating the video card has not resolved the issue, or your video card is on-board and you have access to another known working video card, try an alternative video card in the computer.

Replace video card

If an alternative video card didn't work or you do not have an alternative video card to try, we suggest purchasing a new video card to replace the defective video card in the computer.

• Computer video card buying tips.

If an alternative video card didn't work, and replacing the video card with a new one did not resolve the issue, it's likely a defective motherboard and should be replaced.

Replace motherboard

If all the above steps have not resolved the issue, you have a bad motherboard. If you feel comfortable replacing the motherboard you can find buying tips for motherboardshere. Otherwise we suggest having the computer serviced at a local computer repair shop.

My computer monitor randomly shuts off

There are several possible reasons why a monitor would turn off randomly. Some of the reasons relate to the monitor while others relate to the computer.

Tip: If the monitor is staying on, but loosing signal (e.g. the power light goes from green to orange) this is almost always an issue with the computer and not the monitor. If the monitor power light turns off, then it is almost definitely a problem with the monitor.

Monitor overheating

One reason the monitor could shut off is because it is overheating. When a monitor overheats, it will shut off to prevent damage to the circuitry inside. Causes of overheating can be dust build-up inside the monitor, external heat or humidity where the monitor is used (especially on a hot summer day), or other blockage of the slits or holes that allow the heat to escape.

If the monitor is overheating, it is best to unplug the monitor and let it cool down fully before using again. Then, if you have canned air (anti-static, for electronics), try to blow out any dust that may be inside the monitor casing. If the room where the monitor is being used is very hot, find a way to cool it down, either by turning on a fan or the air conditioning system. Wait until the room cools down some before trying to use the monitor again.

Also, if you're using an older CRT monitor, upgrading to a newer flat panel display will resolve many heat related issues in a hot environment.

Loose cable

Although not as common, if the power cord is loose and is not securely connected to the back of the monitor it will cause the monitor to turn off. This can cause a loss in power, resulting in the monitor shutting off. Make sure the power cord is firmly in place in the back of the monitor. It's also possible that the power connector in the monitor is going bad and not receiving adequate power from the power cord. In this case, it is typically best to replace the monitor instead of having it repaired.

Bad Monitor

Another reason the monitor could shut off is because of a malfunction in the circuitry. There could be a short in the wiring or some other failure in the circuitry, causing the picture to go black or causing the monitor to shut off completely. In this case, there may not be much you can do other than buying a new replacement monitor. Monitors are usually not economical to have repaired since the repair cost can cost more than the price of a new monitor. You could bring the monitor to a computer repair shop to have it looked at, but most likely they will also recommend replacing the monitor.

COMPUTER OPERATING SYSTEM

An operating system or OS is a software program that enables the computer hardware to communicate and operate with the computersoftware. Without a computer operating system, a computer and software programs would be useless. In the picture to the right, is an example of Microsoft Windows XP, a popular operating system and what the box may look like if you were to visit a local retail store to purchase it.

When computers were first introduced the user interacted with them using a command lineinterface, which required the user to perform a series of commands in order to interact with the computer and its hardware and software. Today, almost every computer is using a Graphical User Interface (GUI) operating system that is much easier to use and operate.

Examples of computer operating systems

Microsoft Windows 7 - PC and IBM compatible operating system. Microsoft Windows is the most commonly found and used operating system.
Apple MacOS - Apple computer operating system. The only Apple computer operating system.
Ubuntu Linux - A popular variant of Linux used with PC and IBM compatible computers.
Google Android - operating system used with Android compatible phones.
iOS - Operating system used with the Apple iPhone.

How to Check a PC Operating System

An operating system (OS) is software that manages the interaction between hardware resources and the programs or applications you use on a computer. Most PCs have a version of the Windows operating system on them but Macintosh, Linux and UNIX are other popular operating systems. Besides learning the name of your operating system, such as whether you have Windows 7, you can find other useful information about your system. If you are worried about taxing your computer's central processing unit (CPU), for example, you may be able to check your operating system's bit version. A 64-bit version of Windows can process higher amounts of random access memory (RAM) better than a 32-bit version. Follow these methods to check a PC operating system.

Steps

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   Turn on your PC. Watch as the computer starts up.
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   Check whether your operating system name, such as "Windows Vista," is displayed. If you do not see your operating system or want more details about it, let your computer finish starting up.
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   Click the "Start" button if there is one. It is found in the lower left corner of the Desktop. A "Start" button means you have the Windows 95 OS or later.
   • If you do not have a "Start" button, look for other indicators that show what operating system you have.
   • A Microsoft Windows logo or flag may mean you have a version of Windows that predates Windows 95, such as Windows 3.11.
   • If you see a red hat in a corner of your screen, you are running the Red Hat Linux operating system.
   • If you see a green or blue "L" in a screen corner, you have Lindows or Linspire.
   • A gray or black footprint in a screen corner indicates you are using a graphical user interface (GUI) called GNU Network Object Model Environment (GNOME) on a form of Linux or UNIX.
   • The Sun Solaris operating system is being used with X, a graphics system for UNIX, if you have a purple background with "Sun" or "Solaris" being visually indicated on your screen.
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   See if there is text written down the side of the "Start" menu. The text may name your PC's operating system and edition such as "Windows 95," "Windows 2000 Professional," "Windows XP Home," etc.
   • If you are not sure if the text shown is the name of your operating system or you want more information on the OS, try 1 of the options below.
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   Type "winver" without quotation marks in the "Start" menu's search box, then press "Enter."
   • You may need to choose "Run" in the "Start" menu, then type in "winver" without quotation marks. Press "Enter."
     
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   Look for an "About Windows" window to appear. The name of the OS should be in the top portion of the window.
   • The version number of the operating system will be shown after the word "Version" and any service pack that has been installed as an upgrade will be displayed in parentheses. An example would be "Version 6.0 (Build 6001: Service Pack 1)."
     
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   Right click the "My Computer" icon as an alternative. It can usually be found on your Desktop or in your "Start" menu.
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   Select "Properties" from the menu that appears.
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   Look at the "System Properties" window that displays. More detailed information on your operating system can be found under the "General" tab after "System:" or "System type," such as whether you are running a 64-bit or 32-bit version of Windows.
   • See what operating system edition you are running near the top of the window under "System:" or "Windows edition." An example is "Windows XP Home."
   • If running an edition of Windows XP, look for "x64 Edition" to see if you have the 64-bit version. If it is not there, you have the 32-bit version.
   • For an edition of Windows Vista or Windows 7, look for "64-bit Operating System" or "32-bit Operating System" next to the words "System type."

COMPUTER HARDWARE

Definition: Hardware, in the computer world, refers to the physical components that make up a computer system.

There are many different kinds of hardware that can be installed inside, and connected to the outside, of a computer.

Take a tour inside your PC to learn how all the hardware in your computer connects together to create the complete computer system you use everyday.

Here are some common individual computer hardware components that you'll often find inside a modern computer case:

• Motherboard
• Central Processing Unit (CPU)
• Random Access Memory (RAM)
• Power Supply
• Video Card
• Hard Drive (HDD)
• Solid-State Drive (SSD)
• Optical Drive (e.g. BD/DVD/CD drive)
• Card Reader (SD/SDHC, CF, etc.)

Here is some common hardware that you might find connected to the outside of a computer:

• Monitor
• Keyboard
• Mouse
• Battery Backup (UPS)
• Printer
• Speakers

Here is some less common computer hardware, either because these pieces are now usually integrated into other devices or because they've been replaced with newer technology:

• Sound Card
• Network Interface Card (NIC)
• Expansion Card (Firewire, USB, Thunderbolt, etc.)
• Hard Drive Controller Card
• Analog Modem
• Scanner
• Floppy Disk Drive
• Joystick
• Webcam
• Microphone
• Tape Drive
• Zip Drive

The following hardware is referred to as network hardware and various pieces are often part of a home or business network:

• Digital Modem (e.g. Cable Modem, DSL Modem, etc.)
• Router
• Network Switch
• Access Point
• Repeater
• Bridge
• Print Server
• Firewall

Network hardware isn't as clearly defined as some other types of computer hardware. For example, many home routers will often act as a combination router, switch, and firewall.

In addition to all the items listed above, there's more computer hardware that I like to callauxiliary hardware, of which a computer might have none, or several, of some kinds:

• Fan (CPU, GPU, Case, etc.)
• Heat Sink
• Data Cable
• Power Cable
• CMOS Battery
• Daughterboard

How to Become Computer Literate

Steps

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   Find a real person to help you; not just someone online. Some good people to ask are your own kids. They know a lot about the computer, but they may be annoyed if you ask too much. Also, check out some books at the library about computers. There are a couple of good books out there.
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   Learn the basic steps to get on the computer. Learn how to turn the computer on, off, on standby if applicable, how to log off if using Windows XP, and how to put discs in the disc drive.
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   Learn about the assorted programs and applications that you will be using.Install them on the computer by placing the CD into the disc drive, and following the installation wizard that pops up on the screen. After installing, play around with the application. this will help you understand the program better.
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   Learn a little about some of the chat jargon or chatspeak. Some examples are "lol" (laugh out loud), and "btw" (by the way). Also pay attention to - 1337 speak, which means "leet" or "elite". You won't really need to worry about Elite speak, as it was mainly used by hackers and crackers in the 1990s. Now it is mainly used by "wannabe" hackers, so you are most likely safe. Check out the external links for more information. Also, remember that this will help you figure out what you children are saying online when you look at their IMs, or instant messages.
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   Remember that there are some programs which can send where your child is going online right to your email inbox.
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   Set up an email account, which will be required to register with just about any website that allows posting messages (ie: forums, blogs, and sites with built-in chat rooms or IRC clients). Find a free email provider you like such as Google, Yahoo, Hotmail, or AOL. Sign up using their instructions.
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   Learn a little about bad people online. First, there are pedophiles which are a danger to your kids. There are also scams, viruses, cookie grabbers, and Trojan horses. See external links for more info. Also, always keep your computer up to date with security patches and other updates. Learn to recognize spam and forged emails some of which can look very real. Learn about money mule scams so that you do not fall for them.
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   Learn to protect your computer by installing anti-spy and anti-virus software.
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   Explore a little on the web. Visit Google.com to search for sites that focus on some of your interests.