COMPUTER HARDWARE

Motherboards

The most important part of any computer is the motherboard. As the name implies a motherboard is the mother of all other components in a computer.
The motherboard brings all the core components together such as the Central Processing Unit (CPU), Memory and Hard Disks. In short, the motherboard connects and allows all of the components in the computer to work together.
There are two different types of Motherboard: AT style and ATX style.

AT Motherboards

The AT-style motherboards represent the classic approach to component placement. AT-motherboards are available in two variations, the baby AT and the full AT. Both variations simply refer to the overall dimensions of the board.
AT Boards are generally found in older systems, typically those that use the now aged Pentium Processor. The Majority of AT motherboards had a single keyboard port soldered to the motherboard
The I/O ports (e.g. USB, COM and PS/2 ports) are separate from the motherboard and are placed on a riser card or separate headers.
To identify an AT motherboard first check the power connectors. AT Motherboards use two sets of 6-pin inline power connectors
Caution it is possible to plug these connectors in the wrong order and fuse the motherboard

ATX Motherboards

The ATX-style motherboards are a result of the industry’s push for standardization and are found in most systems today. Most modern computers contain an ATX motherboard. ATX boards can use Advanced Power Management.
Distinguished by having more than just one external connector ATX boards have Keyboard, Mouse, Serial, Parallel and USB connectors.
ATX boards can also be distinguished by the monoblock power connectors. Also available in micro ATX enabling the use of smaller cases.

Motherboard Components

There are two types of receivers for CPU’s
Zero insertion force or ZIF sockets. With a ZIF socket, before the CPU is inserted, a lever or slider on the side of the socket is moved, pushing all the sprung contacts apart so that the CPU can be inserted with very little force (generally the weight of the CPU itself is sufficient with no external downward force required). The lever is then moved back, allowing the contacts to close and grip the pins of the CPU, often with a fan attached for cooling.
Single Edged Contact (SEC) cartridge slot or Slot 1 seen on PII and PIIIs. Developed by Intel to add Cache memory for the processor cheaply. The processor is mounted on a Single Edge Connector Cartridge (SECC), much like a PCI slot, but with a 242-lead edge-connector.

Bridges

There are two main bridges on a motherboard the Northbridge and the Southbridge. Bridges control access to the processor from the peripherals.
The Northbridge, also known as the Memory Controller Hub (MCH), is traditionally one of the two chips in the core logic chipset on a PC motherboard. The Northbridge typically controls communications between the CPU, RAM, AGP or PCI Express, and the Southbridge.. A Northbridge will typically work with only one or two classes of CPUs and generally only one type of RAM. There are a few chipsets that support two types of RAM (generally these are available when there is a shift to a new standard).
The Southbridge, also known as the I/O Controller Hub (ICH), is a chip that implements the “slower” capabilities of the motherboard in a Northbridge Southbridge chipset computer architecture. The Southbridge can usually be distinguished from the Northbridge by not being directly connected to the CPU. Rather, the Northbridge ties the Southbridge to the CPU. The functionality found on a contemporary Southbridge includes:PCI bus, ISA bus, SMBus, DMA controller, Interrupt controller, IDE, (SATA or PATA) controller ,LPC Bridge, Real Time Clock, Power management (APM and ACPI) and Nonvolatile BIOS memory

BIOS Chips

The [[BIOS( Basic Input Output System)]] refers to the software code run by a computer when first powered on. The primary function of BIOS is to prepare the machine so other software programs stored on various media (such as hard drives, floppies, and CDs) can load, execute, and assume control of the computer. This process is known as booting up.
The BIOS is stored as a ROM (Read-Only Memory) program and is retained when the machine is turned off. Settings within the BIOS may be changed by the user and these changes are stored in the BIOS memory this is maintained by a trickle of charge from the BIOS battery.

Memory

SIMMS- Single Inline Memory Modules. An older type of memory only seen on very old motherboards came in 30 pin modules and 72 pin modules.
SDRAM chips are rated according to their maximum clock rate and their read cycle time. Common clock ratings include 66MHz, 100MHz, and 133MHz. Common read cycle times include 50ns and 60ns.
DDR SDRAM or double-data-rate synchronous dynamic random access memory is a type of memory integrated circuit used in computers. It achieves greater bandwidth than ordinary SDRAM by transferring data on both the rising and falling edges of the clock signal (double pumped). This effectively nearly doubles the transfer rate without increasing the frequency of the front side bus.
Stick/module specification
PC-1600: DDR-SDRAM memory module specified to operate at 100 MHz using DDR-200 chips, 1.600 GByte/s bandwidth
PC-2100: DDR-SDRAM memory module specified to operate at 133 MHz using DDR-266 chips, 2.133 GByte/s bandwidth
PC-2700: DDR-SDRAM memory module specified to operate at 166 MHz using DDR-333 chips, 2.667 GByte/s bandwidth
PC-3200: DDR-SDRAM memory module specified to operate at 200 MHz using DDR-400 chips, 3.200 GByte/s bandwidth

Drive Connectors

Integrated Device Electronic (IDE)
[Integrated Device Electronic (IDE)]] connectors connect the motherboard, via a ribbon cable to various peripherals, the most common being hard drives and CD ROMs. On most boards there are 2 channels/connectors, each can have 2 devices attached giving a total of four IDE devices.
If one device is attached to a cable, it should be configured as the master. If two devices are attached to the same cable then one must be the master device and one the slave. Master and slave are configured by the use of jumpers. Jumpers are small, insulated sleeves with a contact inside used to complete a circuit

Hard Disks

Hard disks are used to store data in a non-volatile form within the machine. I.e. the data remains intact even if the power to the device is cut off. Data is stored as magnetic ones and zeros on a steel platen and is read by pickup arms that scan the drive as the platens spin
Most major hard drive and motherboard vendors now support self-monitoring, analysis, and reporting technology (S.M.A.R.T.), by which impending failures can be predicted, allowing the user to be alerted to prevent data loss.The mostly sealed enclosure protects the drive internals from dust, condensation, and other sources of contamination. The hard disk’s read-write heads fly on an air bearing which is a cushion of air only nanometers above the disk surface. The disk surface and the drive’s internal environment must therefore be kept immaculate to prevent damage from fingerprints, hair, dust, smoke particles, etc., given the submicroscopic gap between the heads and disk.

Floppy Disks

The floppy disc controller is generally situated near the IDE controllers and in fact looks like a small IDE slot
The ribbon has a twist and the first floppy drive (A: drive) should be placed after the twist if the cable has more than three connectors. If the cable is really old it may have a connector for a 5 1/4 Floppy drive.

SCSI

SCSI stands for “Small Computer System Interface”, and is a standard interface and command set for transferring data between devices on both internal and external computer buses. SCSI is most commonly used for hard disks and tape storage devices, but also connects a wide range of other devices, including scanners, printers, CD-ROM drives, CD recorders, and DVD drives. In fact, the entire SCSI standard promotes device independence, which means that theoretically SCSI can be used with any type of computer hardware.
On a parallel SCSI bus, a device (e.g. host adapter, disk drive) is identified by a “SCSI ID”, which is a number in the range 0-7 on a narrow bus and in the range 0-15 on a wide bus.

SATA

Serial ATA (SATA) is a computer bus technology primarily designed for transfer of data to and from a hard disk. It is the successor to the legacy AT Attachment standard (ATA). This older technology was retroactively renamed Parallel ATA (PATA) to distinguish it from Serial ATA. Both SATA and PATA drives are IDE (Integrated Drive Electronics) drives, although IDE is often misused to indicate PATA drives.
The two SATA interfaces, SATA/150, runs at 1.5 GHz resulting in an actual data transfer rate of 1.2 Gigabits per second (Gb/s), or 150 megabytes per second (MB/s). SATA II 3Gb/s resulting in an actual data transfer rate of 2.4 Gb/s, or 300 MB/s.

Motherboard Slots

To add more functionality to a computer, cards such as network or video cards can be added. Sometimes these functions are built into the motherboard. There are several types of expansion slots:
The PCI (Peripheral Component Interconnect) The PCI bus is common in modern PCs, where it has displaced ISA as the standard expansion bus, but it also appears in many other computer types.
PCI 2 33.33 MHz clock with synchronous transfers peak transfer rate of 133 MB per second for 32-bit bus
PCI 2.2 allows for 66 MHz signalling (requires 3.3 volt signalling) (peak transfer rate of 503 MB/s) PCI 2.3 permitted use of 3.3 volt and universal keying, but did not support 5 volt keyed add in cards.
PCI 3.0 is the final official standard of the bus, completely removing 5 volt support.
ISA/EISA; Industry Standard Architecture and Extended Industry Standard Architecture An older type of bus connector. Considered obsolete
PCI Express, PCIe, or PCI-E is an implementation of the PCI computer bus that uses existing PCI programming concepts, but bases it on a completely different and much faster serial physical-layer communications protocol. PCIe transfers data at 250 MB/s (238 MiB/s), per channel to a maximum of 16 channels, a total combined transfer rate of 4GB/s (3.7 GiB/s). Almost all of the high end graphics cards being released today use PCI Express. NVIDIA uses the high-speed data transfer of PCIe for its newly developed Scalable Link Interface (SLI) technology, which allows two graphics cards of the same chipset and model number to be run at the same time, allowing increased performance.
The Accelerated Graphics Port (also called Advanced Graphics Port) is a high-speed point-to-point channel for attaching a graphics card to a computer’s motherboard, primarily to assist in the acceleration of 3D computer graphics. Some motherboards have been built with multiple independent AGP slots. AGP is slowly being phased out in favour of PCI Express.
AGP 1x, using a 32-bit channel operating at 66 MHz resulting in a maximum data rate of 266 megabytes per second (MB/s), doubled from the 133 MB/s transfer rate of PCI bus 33 MHz / 32-bit; 3.3 V signaling.
AGP 2x, using a 32-bit channel operating at 66 MHz double pumped to an effective 133 MHz resulting in a maximum data rate of 533 MB/s; signaling voltages the same as AGP 1x;
AGP 4x, using a 32-bit channel operating at 66 MHz quad pumped to an effective 266 MHz resulting in a maximum data rate of 1066 MB/s (1 GB/s); 1.5 V signaling;
AGP 8x, using a 32-bit channel operating at 66 MHz, strobing eight times per clock, delivering an effective 533 MHz resulting in a maximum data rate of 2133 MB/s (2 GB/s); 0.8 V signaling.

Peripheral Connections

There are a number of ports on the motherboard for the connection of additional devices:.
Serial ports connected the computer to devices such as terminals or modems. Mice, keyboards, and other peripheral devices also connected in this way.
Parallel ports are most often used to communicate with peripheral devices. The most common kind of parallel port is a printer port, such as a Centronics connector based port which transfers eight bits at a time. Disk drives are also connected via special parallel ports, such as those used by the SCSI and ATA technlogies. However, when people refer to a parallel port, they are usually referring to a printer port, either on a printer or a PC.
A USB system has an asymmetric design, consisting of a host controller and multiple daisy-chained devices. Additional USB hubs may be included in the chain, allowing branching into a tree structure, subject to a limit of 5 levels of branching per controller. No more than 127 devices, including the bus devices, may be connected to a single host controller. Modern computers often have several host controllers, allowing a very large number of USB devices to be connected. USB cables do not need to be terminated.
USB supports three data rates.
A Low Speed rate of 1.5 Mbit/s (183 KiB/s) that is mostly used for Human Interface Devices (HID) such as keyboards, mice, and joysticks.
A Full Speed rate of 12 Mbit/s (1.5 MiB/s). Full Speed was the fastest rate before the USB 2.0 specification and many devices fall back to Full Speed. Full Speed devices divide the USB bandwidth between them in a first-come first-served basis and it is not uncommon to run out of bandwidth with several isochronous devices. All USB Hubs support Full Speed.
A Hi-Speed rate of 480 Mbit/s (57 MiB/s).

HOW TO INSTALL WINDOWS 7

WATCH VIDEO TO SEE HOW TO INSTALL WINDOWS XP

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How to Uninstall Stubborn Programs?

“There are a few programs that I installed on my computer a few months back due to which my computer has been getting stuck a lot. Now I want to delete them all, but even though I tried different ways to delete and remove those programs, none worked. What should I do now? How should I remove these programs?”

Have you been at the receiving end of a particularly stubborn program that just refuses to budge? Maybe the programs won’t start. No matter how many times you try to try to delete it, uninstall it, it just would not get uninstalled? Well, not to worry because through this post you will show you how you can delete even the most obstinate of programs. These simple steps would help all, novices and pros alike.

How to Uninstall Stubborn Programs?

There are mainly two ways through which you can remove unwanted installed programs.

• Use Add/Remove programs which can be found in the Control Panel and select the software or the program that you want to uninstall. Lastly click the ‘Remove’ button to uninstall.
• Use third party software to uninstall the stubborn program.

#1. Add or Remove Programs

Before you try any complicated steps in order to remove your installed programs, it is better to try your luck through the ‘Add or Remove Program’ option, which can be found in the Control Panel or the Start menu.
1: Go to Control Panel through Start Menu, and click on the “Add or Remove Programs” icon.

2: Select the software you wish to uninstall and click the remove option.
3: After you click the remove button, a prompt will pop up which will ask you to confirm whether you really want to uninstall the software or not and so you can ultimately remove the program.
Note: If your program still doesn’t get uninstalled or if you can’t even locate it in the programs list, then what you can do is search within the C: drive as it contains numerous hidden files and programs. You can make these hidden files visible in order to remove or uninstall them.

Show Hidden Files

1: Go to Control Panel through Start Menu.
2: Click “Appearance and Personalization” icon. Under Folder Options, you will find an option “Show Hidden Files or Folders”.

3: Uncheck the boxes which are labeled ‘Hide extensions for known file types’ and ‘Hide protected operating system files’.

4: Lastly click Apply. You have successfully made the hidden files and folders visible.
SAFE MODE:
Safe mode prevents the computer from being affected when you uninstall a program. If an install is not getting uninstalled it may be due to it containing malware characteristics or it being in the form of other similar unwanted applications. Hence if you start your computer in Safe Mode, you can ensure that any intrusions won’t be affecting your PC as Safe Mode disconnects internet and only allows programs that actively affect the system. So what are the steps to safely switching your computer to Safe Mode and following it up with uninstalling the programs of your choice?
1: Start your computer or laptop and at the first screen before Windows login comes into sight, hold down F8 button (which can be found on your keyboard).
2: Use the arrow keys that you see in the boot menu to navigate through the page and highlight as well click over the Safe Mode option available.

3: After you have selected the Safe Mode option, log in to your computer normally.
4: Once your computer starts, run a virus scan with your antivirus to prevent any multiple malware threats during the scan to ensure a more thorough scan.
5: Uninstall the program of your choice.
6: After you’ve successfully uninstalled the offending program, run through a virus scan and shut your computer down. After that start your computer again, and you will find it to be working normally again.

#2. Software Tools to Remove Windows Applications

If you have tried the Safe Mode action as well as ‘Add or Remove Programs’ tool, and the program you want removed is still installed, then you know time has come to take a stronger action. And what might be the stronger action required here? Well, there are numerous tools available on the internet market which you can install in order to remove certain programs that you don’t wish to have on your computer. Below are some of the best tools mentioned amongst a plethora of them available, to ease your worries.
• Revo Uninstaller Free: Revo Uninstaller is a widely acclaimed tool which helps in uninstalling unwanted programs. It includes registry-cleaning as well as uninstalling programs. It has a pro version as well which is fairly priced and ensures faster service and more mature clean up along with a few essentials not included in the standard version.
• AppRemover: Another great tool that not only ensures that your files are removed, but also takes care of the registry entries. It works best with security tools. When you’re trying to switch to a different security tool, it helps in cleaning the previous tool as well as the registry entries that it left in its wake. Moreover, it is also used to search for files and Registry entries that have been leftover.
• IOBit Uninstaller: This freeware ensures that your files are removed with minimum hassles. It has a standard mode which involves basic uninstall and an advanced mode which involves removal of registry entries and files comprehensively.
These are the few ways through which you can uninstall some of the most stubborn programs as well with minimum complications and hassles.

                                                             seee youuuuuuuu

10 Computer Safety Tips – Basic and Free

www.tips4pc.com

The best computer safety tips aren’t just the ones that can save you money as free doesn’t always mean no cost—they also save you money over the long term by keeping you and your computer out of trouble. So whether you want to save money or you just want to avoid spending it, try these 10 tips:

1—Anti-Virus And Firewall - Use It

Almost all new computers today come with free anti-virus and firewall software. Often it’s only free for 60 or 90 days and then you have to start paying for it, but you should use that free trial period to get your money’s worth.
After the trial ends, you can switch to free firewall and anti-virus software. For a free firewall, use the firewall built into Windows. It’ll protect you from everything a more expensive firewall will protect you from. Its only downside is that it isn’t as configurable as a paid firewall.
For free anti-virus, I suggest AVG. It may not be as good as the top-tier paid anti-virus products, but it’s close. If you avoid risky behaviors such as downloading strange programs, AVG should do everything you need for free.

2—Make Backups – Yeah Obvious Stuff

Your computer will die one day. It could be today or it could be years from now, but whenever it happens, you shouldn’t be surprised. Many times computers die suddenly and there’s no chance of recovering any data.
That means you must make good backups every time you do something important on your computer. When I started using computers, backups were hard and time consuming. Today backups are easy and practically instant.
The best backup option  is one that’s stored separately from your computer. That way whatever destroys your computer, such as a house fire, has less chance of destroying your backup. A great way to keep your backup away from your computer is by making your backup over the Internet.
Two online services, Dropbox and Moxy, both offer free online backups. They do severely limit the size of the files you can backup on the free plan, but if you use both services, you get twice the free backup space. You can also increase the amount of backup space you get by paying a modest monthly charge.
Both Dropbox and Moxy automatically backup your files whenever they change—for example, they backup a document every time you hit “Save”. That means your backups always include your most recent data, which is the best type of backup to have.

3—Install Updates ASAP

Do you ever dither when Windows asks you to reboot your computer after an update? Don’t. When Microsoft releases a patch to Windows, they’re also telling the world that there’s something wrong with Windows, and the key to that fault is in that patch—as soon as hackers read the patch, they can start creating viruses which exploit that fault in Windows to break into your computer.
Once you install the patch, you’re safe. But every minute you wait to install the patch leaves you vulnerable in a world that knows exactly how to use your vulnerability.
This same advice to update immediately also applies to other software which updates itself. Whenever possible, apply updates immediately so hackers can’t use known problems to break into your computer. This is very important so you can protect your computer from viruses and hackers alike.

4—Use A Surge Protector

An electrical surge, most often the result of a nearby lightning strike, destroys more computers every year than any other natural event. I find this statistic sad because protecting your computer from electrical surges is so easy: buy a $5 or $10 surge protector from your nearby supermarket or office supply store.
Nothing on this list of computer safety tips could be easier than that. Just buy the surge protector and plug your computer into it and you’ll be safe from every electrical surge except a direct lightning strike on your computer, which is about as likely as you being struck by lightning while inside your house. (Very rare but not impossible.)

5—Go On A Secret Holiday

Don’t tell people online that you’re going on vacation—that is, unless you want to be robbed. If you post about going on vacation to your public Twitter account, any thief can search for “vacation” on Twitter’s main page, find your name, search Google for your address, and break into your house when you’re away.
I advise you not to post about upcoming or current vacations even on somewhat secure sites such as Facebook or Google+. Facebook and Google accounts get hacked everyday and even though hackers rarely engage in physical crime, you have no idea what they’ll do with your information.
Be careful even if you know somebody will be staying home from your vacation—such as your elderly parent or a house sitter. Unless you mention that in every tweet or post, a thief mike get the wrong idea, break into your house, and get into a violent confrontation with your loved one.
It’s safer for you to simply tell everyone about your vacation when it’s over.

6—Don’t Open Exe Files

If someone sends you a program attachment in an email file (even if they claim it’s something else), don’t open it. This is the number one trick hackers use to install viruses on your computer—if you open the file, you install the virus, possibly bypassing your anti-virus software.
If someone really wants you to install a program on your computer, ask them to send you a link to a review of the software on a reputable site—and then download the software from that site.
This is why we always recommend you install decent protection for your computer, especially if you use if often and care about the data it holds. Pc Pitstop’s PcMatic is proving to be a one of the top software programs and has earned a number of awards for actually finding viruses where other programs would not detect. Get a free scan and give it a try.

7—Don’t Trust The From Address

Email was purposely designed to mimic postal mail in many ways, and one of those ways is the from address. On a regular piece of postal mail, you can write whatever you want in the return address part. I’ve written all sorts of names and addresses in this part: my name, my business name, my parents name (when sending mail for them), etc…
You can do the same thing with the from address in email. Just use your offline email program to change the name and email address to whatever you want.
Unfortunately, hackers can do the same thing. They can send you an email from your mother’s address asking you to send $500 by Western Union Moneygram immediately. When you send the money, you discover it really went to the hackers, not your mother.
The key is never to trust the from address by itself, and if anyone asks you to do anything private, expensive, or out-of-character by email, pick up the phone and give them a call. We all need to be educated about spam email.

8—Beware Of Unprotected WiFi

Anywhere you go where you use unprotected wireless connections is a place where hackers can spy on what you’re doing on the Internet.
You may think that most of the things you do on the Internet are relatively unimportant, but consider how a hacker can abuse them. For example, if you login to your Facebook account over unsecured wifi at a coffee shop, a hacker at the same shop can hijack your Facebook session and pull the same Western Union Moneygram trick described above against all of your friends. It doesn’t take much skill and technology to pull off this sort of attack, so it’s a major threat.
Whenever possible, use a wireless connection secured by a password or by the WPS push-button authentication technique.

10—Use SSL For Financial Information

If you need to send credit card or bank information over the Internet, you need to make sure the security is strong enough to protect your information.
The security technology which has been protecting Internet traffic for over 15 years now is the Secure Socket Layer (SSL) for HTTP, which is usually written HTTPS for HTTP Secure or HTTP SSL.
It used to be that Web browsers indicated a secure connection to a HTTPS sever by putting a lock icon in the address bar of your Web browser, but then some hackers figured out how to beat that technique, so now every Web browser indicates secure websites a little bit differently.
What they all do in common is that they add color to the address bar when you’re visiting a secure site. Looking for this color, usually green or gold, before you enter any financial information is another one of these computer safety tips which is better than free because it can save you money.

A BRIEF COMPUTER HISTORY

The computer as we know it today had its beginning with a 19th century English mathematics professor name Charles Babbage.
He designed the Analytical Engine and it was this design that the basic framework of the computers of today are based on.
Generally speaking, computers can be classified into three generations. Each generation lasted for a certain period of
time,and each gave us either a new and improved computer or an improvement to the existing computer.
First generation: 1937 – 1946 - In 1937 the first electronic digital computer was built by Dr. John V. Atanasoff and Clifford Berry. It was called the Atanasoff-Berry Computer (ABC). In 1943 an electronic computer name the Colossus was built for the military. Other developments continued until in 1946 the first general– purpose digital computer, the Electronic Numerical Integrator and Computer (ENIAC) was built. It is said that this computer weighed 30 tons, and had 18,000 vacuum tubes which was used for processing. When this computer was turned on for the first time lights dim in sections of Philadelphia. Computers of this generation could only perform single task, and they had no operating system.
Second generation: 1947 – 1962 - This generation of computers used transistors instead of vacuum tubes which were more reliable. In 1951 the first computer for commercial use was introduced to the public; the Universal Automatic Computer (UNIVAC 1). In 1953 the International Business Machine (IBM) 650 and 700 series computers made their mark in the computer world. During this generation of computers over 100 computer programming languages were developed, computers had memory and operating systems. Storage media such as tape and disk were in use also were printers for output.
Third generation: 1963 - present - The invention of integrated circuit brought us the third generation of computers. With this invention computers became smaller, more powerful more reliable and they are able to run many different programs at the same time. In1980 Microsoft Disk Operating System (MS-Dos) was born and in 1981 IBM introduced the personal computer (PC) for home and office use. Three years later Apple gave us the Macintosh computer with its icon driven interface and the 90s gave us Windows operating system.
As a result of the various improvements to the development of the computer we have seen the computer being used in all areas of life. It is a very useful tool that will continue to experience new development as time passes.
                                COMPUTER FUNDAMENTALS
 
A computer is an electronic machine that accepts data, stores and processes data into information. The computer is able to work because there are instructions in its memory directing it.
The parts of the computer that you can see and touch, such as the keyboard, monitor and the mouse are called hardware. The instructions that direct the computer are called software or computer program.
Data which is raw facts that you the user enter into the computer is called input. This includes; words, numbers, sound and pictures. When the data is entered into the computer, the computer processes the data to produce information which is output. For example, you enter 2+2 into the computer as data, the computer processes it and the result is 4 which is information.
Computers are usually categories into three general categories:
1.Supercomputer – The fastest, largest, most powerful and most expensive computer.
2.Mainframe Computer – This is a little smaller and less powerful than the supercomputer, but, like the supercomputer it is also expensive.
3.Personal Computer (PC)- This is the computer that most people use in their daily lives. This computer is much smaller, less powerful and less expensive than the supercomputer and the mainframe computer. There are two main types of personal computers. Macintosh (Macs) and the PC compatibles (PC). The main differences between the two are the operating systems and the processor they use. This category of computer has two additional types of computers. These are mobile computer and handheld computer. The most popular type of mobile computer is the notebook or laptop computer, and the handheld computer is a very small PC that you can hold in your hand.

It is important to note that, any computer; regardless of its size has an input device, output device and a system unit.
                              COMPUTER HARDWARES
 
Hardware also includes input devices, output devices, system unit, storage devices and
communication devices. Without these components we would not be able to use the computer.
Input Devices - An input device is any hardware component that allows you the user to enter data into the computer.
There are many input devices. Six of the most widely used input devices are:
1. A keyboard -- You use the keyboard to type letters,
numbers,and symbols into the computer.

2. A Mouse --The mouse is a pointing device that has a pointer
that changes into different shapes as you use the mouse.
You click the mouse by pressing and releasing the button.
This action allows you to enter data when using a mouse.

3. A Scanner -- This input device copies from paper into your computer.

4 . A Microphone -- The microphone is usually used for voice input into the computer.

5. A Digital Camer -- The digital camera allows you to take pictures that you can input into your computer.

6. A PC Video Camera -- The PC video camera allows you take both video
and still images that you can input onto your computer.

Output Devices An output device is any hardware component that gives information to the user.
Three commonly used output devices are as follow:
1. A Monitor -- This output device displays your information on a screen,

2. A Printer -- This output device prints information on paper.
This type of printed output is called a hard copy

3.A Speaker -- Sound is the type of output you will get from a speaker.
The other main computer hardware we need to examine is the system unit
         

                                                       it will continue sooon.......... 

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