Tuesday, March 24, 2009

Computer Networking

Computer Networking Basics
Executive summary articles by Kashif Raza

A network is a group of computers, printers and other devices that are co
nnected together with cables. Information travels over the cables, allowing network users to exchange documents and data with each other, print to the same printers and generally share any hardware or software that is connected to the network. Each computer, printer or other peripheral device that is connected to the network is called a node. Networks can have tens, thousands or even millions of nodes.

Network Adapter
A network adapter is connected to the network cabling with a network interface card (also called a "NIC", "nick" or network adapter).

If you're networking a small group of computers together, you may be able to get by with a hub, some 10BaseT cables and a handful or network adapters. Larger networks often use a thin coax "backbone" that connects a row of 10BaseT hubs together. Each hub, in turn, may connect a handful of computer together using 10BaseT cabling which allows you to build networks of tens, hundreds or thousands of nodes. Like network cards, hubs are available in both standard (10Mbps) and Fast Ethernet (100Mbps) versions.

LANs (Local Are Networks)
A network is any collection of independent computers that communicate with one another over a shared network medium. WANs (Wide Are Networks). Often a network is located in multiple physical places. Wide area networking combines multiple LANs that are geographically separate.

This standard defines rules for configuring an Ethernet network as well as specifying how elements in an Ethernet network interact with one another. By adhering to the IEEE standard, network equipment and network protocols can communicate efficiently.

Network protocols are standards that allow computers to communicate. TCP/IP (for UNIX, Windows NT, Windows 95 and other platforms), IPX (for Novell NetWare), DECnet (for networking Digital Equipment Corp. computers), AppleTalk (for Macintosh computers) and NetBIOS/NetBeui (for LAN Manager and Windows NT networks) are the main types of network protocols in use today. Although each network protocol is different, they all share the same physical cabling. This common method of accessing the physical network allows multiple protocols to peacefully coexist over the network media and allows the builder of a network to use common hardware for a variety of protocols.

Computer Network Repair
Executive summary articles by Thomas Morva

Computer networking is very important when it comes to in house office jobs where the mutual connection of computers constitutes an important part of the whole work. Therefore, networking is an important element in today's corporate world.

There are many professional technicians who have the to securely install whatever type of network you require. All networking vendors use the highest quality hardware and software to help insure that your network is trouble free so that you don't have to worry about it. They also troubleshoot and maintain existing networks in homes and offices. Computer network vendors and repairers provide support for all network platforms.

Monday, March 23, 2009

Computer Batteries

Computer Batteries : New Lithium-ion Battery

by Sammy

This computer batteries have compatible models/replace PN : HP/Compaq f4809a f4812a.
With capacity 4400mAh - voltage : 14.8v. Battery Type : Lithium-Ion. 100% OEM compatible!

Lithium-Ion batteries : What You Need to Know About Li-Ion Technology
Summary articles by Mallory Kramer

The difference is in the chemistry, a lithium battery is a disposable power source composed of lithium metal compounds - the key word, here, being disposable. Lithium batteries can not recharged. Lithium Ion batteries on the other hand are intercalated, meaning the lithium ion in side the battery moves between two internal electrodes. This movement or reversibility of the lithium ion accounts for the battery's rechargeability.

What are the benefits of lithium ion technology?
Lithium-ion batteries hold a lot of power and are surprisingly light-weight, especially with consideration to other rechargeable batteries. Li-ion batteries combine single cell technology with a greater energy reservoir than Nickel Metal Hydride and Nickel Cadmium batteries. They store more power for their size than both NiCad and NiMH. Li-ion batteries hold their charge for significantly longer than other comparable batteries and provide steady power until that charge is completely gone. Other batteries gradually and consistently loose power as you work. Li-ion batteries stay strong until the last push.

The disadvantages with using Li-ion battery technology are generally few and far between and technological advancements are making them even less so. Manufacturers have recently improved the lithium-ion recipe to reveal a more reliable battery. Still, every giant has its weaknesses. Li-ion batteries are sensitive to intense hot and cold temperatures. In etreme temperature conditions, the battery will degrade more quickly. Li-ion batteries degrade regardless frequency of use. The Li-ion battery's built-in computer chip tells the battery to refuse a charge once the batteries power falls below a certain point. If this occurs, the battery is beyond repair. Although these defects are more applicable to the older Lithiumion batteries, the possibility of seeing these problems is still worth noting. Fortunately, these said defects are fairly rare and easily avoided. Store Li-ion batteries (and other batteries as well) in a cool, dry place. Use your Li-ion batteries often. Be certain Li-ion batteries have a full charge before storing them and pull them out every so often to use and recharge. Watch the batteries power level to be sure it doesn't fall below the charge limit.