Monday, 28 February 2011

Hub

 hub is rectangular box that is used as the central object on which computers and other devices are connected. To make this possible, a hub is equipped with small holes called ports. Here is an example of a hub:
Although this appears with 4 ports, depending on its type, a hub can be equipped with 4, 5, 12, or more ports. Here is an example of a hub with 8 ports:
When configuring it, you connect an RJ-45 cable from the network card of a computer to one port of the hub.
In most cases for a home-based or a small business network, you may not need a hub.

Network Distribution

Introduction
Building a network consists partly of connecting the computers as we saw in Lesson 1:


One way to do this is to use cables.

Network Cables

Cable is used to connect computers. Although we are planning to use as much wireless as possible, you should always have one or more cables around. In our network, we will use Category 5 cable RJ-45. The ends of the cable appear as follows:
You can purchase this cable from a web store on the Internet. Probably the fastest way to get this cable is to go to a computer store. When purchasing it, get something with at least 6ft.



Using Barebone Computers

A computer is referred to as "barebone" if it's built almost from scratch by assembling its parts. You can build your own computer or you can purchase one. You can purchase or acquire a computer with all parts or only some parts. To get this type of computers:
  • You can go to one of those small computer stores on major streets, describe to them what you want. They would get the parts together and assemble them for you
  • You can shop in a web store such  and click the "Barebone" link
  • You can investigate how to build a computer from scratch, purchase the parts one by one, and assemble them yourself
You may have a computer without an operating system. For example, you might have formatted the hard drive or you might have created two or more partitions on the hard drive and (may be intentionally) loose the operating system. You may plan to use such a computer as a workstation.
Whether you build your own computer or use one without an operating system, before installing Microsoft Windows XP Professional, make sure the computer meets these hardware requirements:
  • A processor with 300 megahertz or higher processor clock speed recommended; 233 MHz minimum required (single or dual processor system);* Intel Pentium/Celeron family, or AMD K6/Athlon/Duron family, or compatible processor recommended
  • 128 megabytes (MB) of RAM or higher recommended (64 MB minimum supported; may limit performance and some features)
  • 1.5 gigabytes (GB) of available hard disk space
  • Super VGA (800 x 600) or higher-resolution video adapter
  • CD-ROM or DVD drive
  • As many USB ports as possible
  • Mouse and Keyboard ports
Because building a barebone depends on your goals, we will not review here the parts to acquire or the steps performed.


Using Existing Computers

Using Existing Computers

If you already have one or more computers that you plan to use as workstations, you can start by checking the hardware parts installed in the computer. The computer must meet the following requirements

  • Processor: An Intel Pentium or Celeron family of processors or an AMD K6/Athlon/Duron family of processors. The processor should have a 300 megahertz clock speed. A higher speed is recommended.
    To check the speed of the processor of a computer, you have many alternatives:
     
o                                When the computer starts, you can access its BIOS by pressing F2 or F8 depending on the computer, the model or the manufacturer
o                                From the computer's desktop, if it's running Windows 95 and later, you can right-click My Computer and click Properties
o                                You can open Control Panel and double-click System
With these two previous options, you can see the processor's speed in the Computer section of the General property page.
As another alternative to check the computer's processor, from Control Panel, you can double-click System, click the Hardware tab, and click Device Manager. In the Device Manager window, expand the Processors node and double-click the first node under Processors. Here is an example:
  • In most cases, if your computer is running Microsoft Windows XP Home Edition, it should be ready for Windows XP Professional. If the computer is running another operating system but it appears to be too slow, you can replace its processor with a faster one. Before replacing a processor, you must first find out what type of processor your computer use. You cannot just replace any processor for another. To know the type of processor your computer uses, you have three options:
You can check the documentation (manual or user guide) that came with your computer. A page in it should describe the type of processor your computer is using. You can write it down and, when you go to a computer store or to a web store and use this description to purchase a new one. You can purchase a new processor from a computer store or from one of the following web sites:
o                                You can open the computer. In this case, remove the processor. Take it to a computer store and tell the sales people that you want a faster processor

You can call the manufacturer of your computer. They will ask the serial number or the make/model. They will tell you the type of processor installed in it. You can also tell them that you want to purchase a faster processor 
If you purchase or acquire a processor, it is usually easy to install and it comes with easy to-follow instructions. You will need to open the computer. It may be a good idea to take it

to a computer store or a computer repair shop and have them replace the processor for you
  • RAM: The computer must have a memory of at least 64 megabytes (MB). As memory is not particularly expensive nowadays, you should upgrade the computer's memory to at least 512MB
To check the amount of RAM your computer has:

o                                When the computer starts, you can access its BIOS by pressing F2 or F8 depending on the computer, the model or the manufacturer
o                                From the desktop of a Windows 95 and later computer,  you can right-click My Computer and click Properties
o                                You can open Control Panel and double-click System
Any of these two options would show the computer's memory in the General  property page under the Computer section. Here is an example:


If your computer doesn't have enough memory, you can increase it. Like a processor, different computers use different types of memory. Before changing or increasing the memory of your computer, you should find out what type it takes. As mentioned for the processor, you can get this information by consulting the manual it came with, by opening the computer, or by calling the manufacturer.
Computer memory has not been very expensive lately. You can purchase the one appropriate for your computer from a computer, from the manufacturer of your computer, or from a web store. Once you get the memory, you can open the computer and insert the new memory in the sockets next to the existing memory
Hard Drive: Before installing Microsoft Windows XP Professional on an existing computer, make sure the hard drive has the appropriate capacity to handle the OS. To find out how much space your hard drive has, you can open Windows Explorer or My Computer, right-click the C:\ drive and click Properties. Here is an example:


The computer may have more than one drive or many partitions
In this case, you can check the drive or partition you intend to use to install the new operating system.

The hard drive or the partition you intend to use should have at least 1.5 gigabytes (GB) of available hard disk space

  • Video: The computer should have Super VGA video adapter and be able to handle at least an 800 x 600 or higher-resolution.
    To check the current video resolution of your computer, right-click the desktop and click Properties. You can also open Control Panel and double-click Display. In the Display Properties, click Settings:
    To check the video adapter of your computer, click Advanced and click the Adapter tab.

  • CD-ROM or DVD drive: Unless you got this computer a long time ago, it should already have either a CD or a DVD drive or both. If it doesn't, you use one of its empty bays to install one. If the installation seems difficult or something you don't feel like doing, you can purchase an external drive. To do this, you can shop to a computer store or a web store.


  • Network Hardware 1

    Introduction

    As introduced in the previous lesson, in a network, computers and optional other devices are connected to share resources. When a computer or device A is requesting a resource from another computer or device B, the item A is referred to as a client. Because all or most items that are part of a network live in association or cooperation, almost any one of them can be referred to as a client. Based on this, there can be different types of clients. The most regularly used of them is referred to as a workstation

    As its name implies, a workstation is a computer on which a person performs everyday regular assignments. A workstation is primarily a personal computer (PC). It can also be a laptop. You have probably used PCs so far. Almost any modern PC can be used as a workstation and participate on a network.
    Before building a computer network, when planning the workstations, you may be in one of the following scenarios.
    Using New Computers
    If you haven't bought the computer(s) but are planning to, refer to our section on purchasing or acquiring new computers in the Lesson 4.
    

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