Computer Components

Computers are made of the following basic components:

1. Case with hardware inside:
   
   
   1. Power Supply - The power supply comes with the case, but this component is mentioned separately since there are various types of power supplies. The one you should get depends on the requirements of your system. This will be discussed in more detail later
      
      
   2. Motherboard - This is where the core components of your computer reside which are listed below. Also the support cards for video, sound, networking and more are mounted into this board.
      
      
      1. Microprocessor - This is the brain of your computer. It performs commands and instructions and controls the operation of the computer.
      2. Memory - The RAM in your system is mounted on the motherboard. This is memory that must be powered on to retain its contents.
      3. Drive controllers - The drive controllers control the interface of your system to your hard drives. The controllers let your hard drives work by controlling their operation. On most systems, they are included on the motherboard, however you may add additional controllers for faster or other types of drives.
      
      
   3. Hard disk drive(s) - This is where your files are permanently stored on your computer. Also, normally, your operating system is installed here.
      
      
   4. CD-ROM drive(s) - This is normally a read only drive where files are permanently stored. There are now read/write CD-ROM drives that use special software to allow users to read from and write to these drives.
      
      
   5. Floppy drive(s) - A floppy is a small disk storage device that today typically has about 1.4 Megabytes of memory capacity.
      
      
   6. Other possible file storage devices include DVD devices, Tape backup devices, and some others.
   
   
2. Monitor - This device which operates like a TV set lets the user see how the computer is responding to their commands.
   
   
3. Keyboard - This is where the user enters text commands into the computer.
   
   
4. Mouse - A point and click interface for entering commands which works well in graphical environments.

These various parts will be discussed in the following sections.

Computer Classifications

All the computers are designed by the qualified computer architectures that design these machines as their requirements.
A computer that is used in a home differs in size and shape from the computer being used in a hospital. Computers act as a server in large buildings, while the computer also differs in size and shape performing its job as a weather forecaster.
A student carrying a laptop with him to his college is different in shape and size from all the computers mentioned above.
Here we are going to introduce different classifications of computers one by one. We will discuss what are in classifications and what job they perform.
Super computer
The biggest in size, the most expensive in price than any other is classified and known as super computer. It can process trillions of instructions in seconds. This computer is not used as a PC in a home neither by a student in a college.
Governments specially use this type of computer for their different calculations and heavy jobs. Different industries also use this huge computer for designing their products.
In most of the Hollywood’s movies it is used for animation purposes. This kind of computer is also helpful for forecasting weather reports worldwide.
Mainframes
Another giant in computers after the super computer is Mainframe, which can also process millions of instruction per second and capable of accessing billions of data.
This computer is commonly used in big hospitals, air line reservations companies, and many other huge companies prefer mainframe because of its capability of retrieving data on a huge basis.
This is normally to expensive and out of reach from a salary-based person who wants a computer for his home.
This kind of computer can cost up to thousands of dollars.
Minicomputer
This computer is next in he line but less offers less than mainframe in work and performance. These are the computers, which are mostly preferred by the small type of business personals, colleges, etc.
Personal computers
Almost all the computer users are familiar with the personal computers. They normally know what the personal computer is and what are its functions.
This is the computer mostly preferred by the home users. These computers are lesser in cost than the computers given above and also, small in size; they are also called PCs in short for Personal computers.
This computer is small in size and you can easily arrange it to fit in your single bedroom with its all accommodation. Today this is thought to be the most popular computer in all.
Notebook computers
Having a small size and low weight the notebook is easy to carry to anywhere. A student can take it with him/her to his/her school in his/her bag with his/her book.
This is easy to carry around and preferred by students and business people to meet their assignments and other necessary tasks.
The approach of this computer is also the same as the Personal computer. It can store the same amount of data and having a memory of the same size as that of a personal computer. One can say that it is the replacement of personal desktop computer.

Computer Network

Networks are collections of computers, software, and hardware that are all connected to help their users work together. A network connects computers by means of cabling systems, specialized software, and devices that manage data traffic. A network enables users to share files and resources, such as printers, as well as send messages electronically (e-mail) to each other.
Computer networks fall into two main types: client/server networks and peer-to-peer networks. A client/server network uses one or more dedicated machines (the server) to share the files, printers, and applications. A peer-to-peer network allows any user to share files with any other user and doesn’t require a central, dedicated server.
The most common networks are Local Area Networks or LANs for short. A LAN connects computers within a single geographical location, such as one office building, office suite, or home. By contrast, Wide Area Networks (WANs) span different cities or even countries, using phone lines or satellite links.

How Computer Work

Why is it important to know how a computer works?  Easy, if you don't, it will be hard to control.  Computers were never built to control us even though that is how it appears.  Their creation was just another tool God gave man to use to benefit society.  What can you do to learn more about computers?  I have an easy answer.  Just read, and use computers more.  They are not that hard and with time you too can become the master over this tool.
Memory Lets look at computer memory first.  The function of storage in a computer comes in many different sizes, types and shapes.  However there are two basic categories: short-term and long-term.  A typical computer contains numerous types of memory including RAM, ROM, virtual, cache, and various long-term storage devices.  Each type of computer memory serves a specific function and purpose. Computer memory is measured in bytes.  A single byte is made up of a series of 1's and 0's normally traveling in pairs of eight.  These eight 0's and 1's are the way the computer communicates and stores information.  With each keystroke or character a byte of memory is used.  In another article you will learn more about bits and how the computer thinks.
Measuring Memory

Term/Byte	Abbreviation	Value
Bit	none	0 or 1
Byte	B	8 bits  -example: 00100101
Kilo	K, KB	1,024 bytes
Mega	M, MB, Meg	1,048,576 bytes (Million)
Giga	G, GB, Giga	1,073,741,824 bytes (Billion)
Tera	T, TB, Tera	1,099,511,628,000 bytes (Trillion)

Here is another way of looking at the measurement of memory:
Measuring Bytes

8 bits = 1 byte 1000 bytes = 1 kilobyte 1000 kilobytes = 1 megabyte 1000 megabytes = 1 gigabyte 1000 gigabytes = 1 terabyte

ROM
ROM, or read-only memory is permanent, long-term, nonvolatile memory.  Nonvolatile means is doesn't disappear when the computer is shut off.  It also can not be erased or changed in anyway.  However there are types of ROM called PROM that can be altered.  The P stands for programmable.  ROM's purpose is to store the basic input/output system (BIOS) that controls the start-up, or boot process.
RAM
RAM, or random-access memory unlike ROM works only when the computer is turned on.  This memory is vital to the computer because it controls the moment by moment processes of the computer.  The first thing that goes into RAM is the OS (operating system) which is most cases is Windows 95.  Next for the RAM might be a game, or the Internet browser, or some type of software that you want to use.
Early personal computer only needed about 64K of RAM.  Today that number is drastically higher.  With photos, sounds, and even movies going into RAM, the amount need is now in the millions.  The computer I am currently using has 80 MB or 80,000K of RAM.
Multitasking has put more demand on RAM in the past few years.  Multitasking is the ability to run more than one program at the same time.  For instance, many people like to run Netscape Communicator along with their word processing software.  This means you need lots of RAM to hold both programs.
Other types of temporary memory are cache (pronounced "cash") and virtual memory.  Both of these types of memory supplement the computer's primary RAM and perform the same function as RAM.
Storage Devices:
RAM and ROM may be very important parts of the computer; however, without storage devices like hard drives and disk drives your computer would not be near as useful.
Here are the most common forms of Storage Devices found on your home computer:
 

Thumb Drive or Memory Stick	Hard disk (drive) or HD
A device that in 1998 IBM introduced and has caught on very quickly as a great portable storage device.  It quickly replaced the floppy disk. This small device is extremely reliable and fits in the USB port on your computer.  It come in sizes ranging from 1 GB to 64 GB in size.	A stack of round metal platters called disks encased in a metal air tight shell.  They commonly range in sizes from 60  to 500 gigabytes (1000MB=1GB).  The hard drive's function is to store all the files, and software the computer will ever use.  Any file or software program used by RAM most likely will come from the disk drive.
CD-ROM (Compact disk, read-only memory)	DVD-ROM (digital video disk, read-only memory)
CD's function much like hard drive in that they store large amounts of memory.  What separates them is their mobility and optical storage technology.  Their storage capacity is also very limited compared to hard drives.  The can only hold up to approximately 650 MB of information.  The other big difference is that you have to have a special drive to write to CD's.  Otherwise they can only be read from.	DVD's are similar to CD in that they are written and read by laser.  Hard drives use magnetic currents store data.  However CD's and DVD's use light (laser) to write and read data on a disk.  These long and short pits are then stored or etched on the surface of the disk.  They can only be read by laser technology.  The new DVD technology increased the amount of memory a regular CD can hold.  DVD's can range in sizes from 4.34GB (1000MB=1GB)  to 7.95GB.

Processing If someone had to find the brains of the computer they would most certainly say its the microprocessor.  The microprocessor is often referred to as the CPU (Central processing unit).  The microprocessor is a chip the size of a postage stamp.  The processor is the one part of the computer that is most important to the computer.  The microprocessor controls how data is sorted and directs the flow of data. To a great extent a computer is defined by the power of its microprocessor.  Chips with higher processing speed and more recent design offer the greatest performance and access to new technologies.  Most microprocessors made for PCs are made by Intel or by companies that clone Intel chips, such as Advanced Micro Devices (AMD) and Cyrix.
The early Intel chip came in models called 286, 386, and 486.  The 586 chip was given the name Pentium.  The series of Pentiums were given the following names:  Pentium Pro, Pentium with MMX, and Pentium II.  The newer processors hold more transistors and thus more computing power on a single chip.
Microprocessor

Processor	No. of Transistors	Bus Width
80286	134,000	16 bit
80386	275,000	32 bit
80486	1,600,000	32 bit
Pentium	3,300,000	64 bit external/  32 bit internal
Pentium Pro	5,500,000	64 bit
Pentium w/ MMX	4,500,000	64 bit external/  32 bit internal
Pentium II	7,500,000	64 bit
The processor has come a long way and now some of the latest processors are: Celeron · Pentium Dual-Core · Core 2 · Core i5 · Core i7 · Xeon · Itanium  and who know what will come out next?

Input One of the best features of a computer is the ability to give the computer commands and feed it information.  Without an input device this would not be possible.  Input devices can be built into the computer, like the keyboard in a laptop, or it can be connected to the computer by a cable.  The most common input device is the keyboard.  There are lots of others such as: mice, trackballs, touch pads, touch screens, pens, joy sticks, scanners, bar code readers, video and digital cameras, and microphones.  In addition, storage devices such as disk drives can serve as input devices.

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Output Input is important but equally important is the ability to read what the computer is doing.  The computer output devices are used to serve the user.  The most common output device is the monitor, or screen.  However most computer come with speakers and a printer which are excellent output devices.  Storage devices such as disk drives and diskettes also serve as output devices when it is necessary to write new or updated data files to disk or tape.

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Do You Know What Is Computer Systems?

This is the answers:
A complete, working computer. Computer systems will include the computer along with any software and peripheral devices that are necessary to make the computer function. Every computer system, for example, requires an operating system.

Computer Long-long Ago

The first computers did not have electrical circuits, monitors or memory. The abacus, an ancient Chinese adding machine, is one of the original computing machines, used as early as 400 B.C. It can't do many of the computations that a modern electronic calculator can do, but it in the right hands it can make calculating large sums as easy as moving beads around. Famous mathematicians such as Leonardo da Vinci and Blaise Pascal invented more sophisticated calculators using gears and punch cards.