COMPUTER is an electronic machine that follows a set of instructions in order that it may be able to accept and gather data and transform these into information.

TYPES OF COMPUTERS

1. A supercomputer is superficially similar to a mainframe, but is instead intended for extremely demanding computational tasks. As of November 2013[update], the fastest supercomputer in the world is the Tianhe-2, in Guangzhou, China.[9]

An IBM System z9 mainframe

2. A mainframe computer is a much larger computer that typically fills a room and may cost many hundreds or thousands of times as much as a personal computer. They are designed to perform large numbers of calculations for governments and large enterprises.

3. Server Computer with massive hard drive capacity that is used to link other computers together so that data can be shared by multiple users. A computer system in an ambulatory care facility is likely linked or networked with a central server

4. The personal computer, also known as the PC, is one of the most common types of computer due to its versatility and relatively low price.

Some Personal computers are:1. A desktop computer is a personal computer in a form intended for regular use at a single location desk/table due to its size and power requirements. The most common configuration is a computer monitor, keyboard and mouse, and a case that houses the main components of the PC, namely the power supply, motherboard, hard drive, optical drive, and previously the floppy drive.2. Laptops are generally very similar, although may use lower-power or reduced size components.3. A tablet computer is a mobile computer with a touchscreen display, circuitry and battery in a single unit. Tablets come equipped with sensors, including cameras, a microphone and an accelerometer, and the touchscreen display uses finger or stylus gestures substituting for the use of computer mouse and keyboard. They usually feature on-screen, pop-up virtual keyboards for typing.4. Portable computers, which later developed into modern laptops, were originally considered to be a small niche market, mostly for specialized field applications, such as the military, accountancy, for sales representatives etc. As portable computers developed and became more like modern laptops, becoming smaller, lighter, cheaper, and more powerful, they became very widely used for a variety of purposes.5. An embedded system is a special-purpose system in which the computer is completely encapsulated by the device it controls. Unlike a general-purpose computer, such as a personal computer, an embedded system performs pre-defined tasks, usually with very specific requirements. Since the system is dedicated to a specific task, design engineers can optimize it, reducing the size and cost of the product. Embedded systems are often mass-produced, so the cost savings may be multiplied by millions of items.

Some examples of embedded systems include ATMs, cell phones, printers, thermostats, calculators, and videogame consoles.Embedded Computer Sub-Assembly for Accupoll Electronic Voting Machine

COMPONENTS INSIDE THE SYSTEM UNITMotherboardThe motherboard is a sheet of plastic that holds all the circuitry to connect the various components of a computer system.

MotherboardThe motherboard is the body or mainframe of the computer, through which all other components interface. It is the central circuit board making up a complex electronic system. A motherboard provides the electrical connections by which the other components of the system communicate. The mother board includes many components such as: central processing unit (CPU), random access memory (RAM), firmware, and internal and external buses.

Central processing unit (CPU) Small chip found on the motherboard that manipulates the data sent from a program; brains of the computer. Memory

Random Access MemoryRandom access memory (RAM) is fast-access memory that is cleared when the computer is power-down. RAM attaches directly to the motherboard, and is used to store programs that are currently running. RAM is a set of integrated circuits that allow the stored data to be accessed in any order (why it is called random). There are many different types of RAM. Distinctions between these different types include: writable vs. read-only, static vs. dynamic, volatile vs. non-volatile, etc.

read-only memory (ROM)

ROM is "built-in" computer memory containing data that normally can only be read, not written to. ROM contains the programming that allows your computer to be "booted up" or regenerated each time you turn it on. Unlike a computer's random access memory (RAM), the data in ROM is not lost when the computer power is turned off. The ROM is sustained by a small long-life battery in your computer.

(CMOS) complementary metal oxide semiconductorA complementary metal oxide semiconductor (CMOS) is an integrated circuit design on a printed circuit board (PCB) that uses semiconductor technology. The PCB has microchips and a layout of electric circuits that connect the chips. All circuit boards are typically either CMOS chips, N-type metal oxide semiconductor (NMOS) logic, or transistor-transistor logic (TTL) chips. The CMOS chip is most commonly used, as it produces less heat and requires less electricity than the others.

Internal StorageInternal storage is hardware that keeps data inside the computer for later use and remains persistent even when the computer has no power. There are a few different types of internal storage. Hard disks are the most popular type of internal storage. Solid-state drives have grown in popularity slowly. A disk array controller is popular when you need more storage then a single har disk can hold.

Power SupplyThe power supply as its name might suggest is the device that supplies power to all the components in the computer. Its case holds a transformer, voltage control, and (usually) a cooling fan. The power supply converts about 100-120 volts of AC power to low-voltage DC power for the internal components to use. The most common computer power supplies are built to conform with the ATX form factor. This enables different power supplies to be interchangable with different components inside the computer. ATX power supplies also are designed to turn on and off using a signal from the motherboard, and provide support for modern functions such as standby mode.

Computer Video Card very important component in a computerWithout this we cant any information onmoniterit transfers video signals through a cable to yourmonitorvideo card can either be built into themotherboard or be a separate card that is placedin either the AGP or PCI-Express Slots.The computer graphics cards major job in acomputer is to convert graphic patterns intosignals for the monitors screen.2D and 3D effects

3 BASIC COMPONENTS OF COMPUTERControl unit This is the part of the processor that manages the instructions of the programs and makes sure that the other parts of the processor are doing what they should be.

Arithmetic logic unit This is the part of the processor that carries out instructions. It contains circuitry that allows it to perform arithmetic; it allows for logic decisions and acts as a gateway between the processor and other parts of the system.

Memory unit This is where everything is stored; this includes all the program instructions and data required to complete the instructions. The parts of the OS, which the computer is using at the time are also stored here.

MACHINE CYCLEThe steps performed by the computer processor for each machine language instruction received. The machine cycle is a 4 process cycle that includes reading and interpreting the machine language, executing the code and then storing that code.Four steps of Machine cycle1. Fetch - Retrieve an instruction from the memory.2. Decode - Translate the retrieved instruction into a series of computer commands.3. Execute - Execute the computer commands.4. Store - Sand and write the results back in memory.