Motherboard

From Wikipedia, the free encyclopedia

Jump to: navigation, search

The mainboard of a Sony Playstation

The motherboard or mainboard is the main circuit board in a complex electronic system, like a computer. It is the most 'central' part of a computer. All of the different parts of the computer are connected to the motherboard. This lets them work together. In most computers, the motherboard is a big green board, but many come in different colors like black, red and yellow.

[change] "On-board" and "plug-in" parts

Normal electrical parts must be kept on the motherboard. These "on-board" parts include transistors and resistors. Many of the major parts that are attached to the board are able to be removed in the future so that they can be upgraded. The CPU and memory (or RAM) are examples of parts that are usually removable.

Ports on an expansion card

Parts that are not "on-board" can be bought as a card. In fact, many of the on-board parts on today's computers were at one time an expansion card that became very popular. These were put on the board to free up the card slots for other things. Computers today usually have a memory port, 2 or more USB ports, a parallel port (for use with old printers usually), audio & microphone jacks, a network port and ports for the keyboard and mouse. There are also rare motherboards that have plugs only for very specific parts.
All of the slots and plugs both inside and outside the computer case are shaped a certain way to accept a certain type of part. Some will not even accept parts even one generation behind, such as the CPU and memory. Others, like the video plug have not changed in years. Some of the plugs, such as the video, keyboard and mouse plugs, are a special color. These colors make it easier to pair the plug to the port.

Computer memory

From Wikipedia, the free encyclopedia

Jump to: navigation, search

This page or section does not have any sources. You can help Wikipedia by finding sources, and adding them. Tagged since April 2009

The computer memory is a temporary storage area. It holds the data and instructions that the Central Processing Unit (CPU) needs. Before a program can be run, the program is loaded from some storage medium into the memory. This allows the CPU direct access to the program. Memory is a necessity for any computer.
Because the computer is an electrical device, it understands only electricity on and electricity off. This is expressed by using two symbols – 0 and 1 – which are called binary digits or bits. Numbers and text characters are represented as codes, which are made up of combinations of 0s and 1s. The character codes are called ASCII (the American Standard Code for Information Interchange). In ASCII, eight bits – any combination of 0s and 1s – form one character or symbol. For example, the letter A is denoted by the code 01000001. The basic working unit of the computer's memory is therefore a group of eight bits, which is called a byte. The computer's memory consists of many thousands of bytes. To make it easier, the unit K (for kilobytes) can be used to express memory capacity. One K equals 1,024. For example, 64K bytes of memory is the same as 65,536 (1,024 × 64 = 65,536) bytes. For larger memory capacities, the units megagiga can be used. One and megabyte of computer memory usually means 1024 kilobytes, which is 1,048,576 bytes, whereas one gigabyte means 1024 megabytes, which is 1,073,741,824 bytes.
The CPU calls instructions and data from the computer's memory. Because the same computer performs different tasks at different times, the memory is erasable -- much like audio cassette tapes must be erasable to record different musical selections at different times). But there are some programs and instructions which the computer needs. It does not matter what function you are performing. These programs often are permanently recorded in the memory. So they cannot be destroyed. As a result, the computer's memory usually consists of two parts:

[change] Read only memory (ROM)

This is the permanent memory which is used to store important control programs and systems software to perform a variety of functions, such as booting up or starting up programs. ROM is non-volatile. That means the contents are not lost when the power is switched off. Its contents are permanently written at the time of manufacture.

[change] Random access memory (RAM)

RAM is used as the working memory of a computer system. It stores input data, intermediate results, programs, and other information temporarily. It can be read and written. It is volatile, that is all data will be erased when the power is turned off.

Central processing unit

From Wikipedia, the free encyclopedia

(Redirected from Processor)

Jump to: navigation, search

A Pentium CPU inside a computer

A CPU (Central Processing Unit) is an important part of every computer. The CPU is like the brain; its job is to carry out instructions and calculations.
The CPU is an electronic machine that works on a list of things to do. It reads the list, one item at a time, doing each instruction in order. A list of instructions that a CPU can read is a computer program. A machine that can perform the job of a CPU is often called a Turing machine by mathematicians.
Here are some of the basic things a CPU can do:

• Add two numbers together
• Test to see if one number is larger than another
• Move a number from one place to another
• Get a number from memory
• Jump to another place in the instruction list

Even very complicated programs can be made by combining many simple instructions like these. This is possible because each instruction takes a very small time to happen. Many CPUs today can do more than 1 billion instructions in a single second. In general, the more a CPU can do in a given time, the faster it is. One way to measure a processor's speed is MIPS. Flops and CPU clock speed (usually measured in gigahertz) are also ways to measure how much work a processor can do in a certain time.
A CPU is built out of logic gates; it has no moving parts. The CPU of a computer is connected electronically to other parts of the computer, like the video card, or the BIOS. A computer program can control these peripherals by reading or writing numbers to special places in the computer's memory.

Computer hardware

From Wikipedia, the free encyclopedia

Jump to: navigation, search

Computer hardware or hardware means the fixed parts that make up a computer.
Some examples include:

• processor
• memory
• motherboard
• graphics card
• network card
• modem
• USB flash drive
• hard drive

Input and output peripherals

Input and output peripherals

Main article: Peripheral

Input and output devices are typically housed externally to the main computer chassis. The following are either standard or very common to many computer systems.

Wheel Mouse

Input

Main article: Input device

• Text input devices
  • Keyboard - a device to input text and characters by depressing buttons (referred to as keys or buttons).
• Pointing devices
  • Mouse - a pointing device that detects two dimensional motion relative to its supporting surface.
    • Optical Mouse - uses light to determine mouse motion.
  • Trackball - a pointing device consisting of an exposed protruding ball housed in a socket that detects rotation about two axes.
  • Touchscreen - senses the user pressing directly on the display

• Gaming devices
  • Joystick - a control device that consists of a handheld stick that pivots around one end, to detect angles in two or three dimensions and reports its angle or direction to the device it is controlling.
  • Game pad - a hand held game controller that relies on the digits (especially thumbs) to provide input.
  • Game controller - a specific type of controller specialized for certain gaming purposes.
• Image, Video input devices
  • Image scanner - a device that provides input by analyzing images, printed text, handwriting, or an object.
  • Web cam - a video camera used to provide visual input that can be easily transferred over the internet.
• Audio input devices
  • Microphone - an acoustic sensor that provides input by converting sound into electrical signals.

Output

Main article: Output device

• Printer - a device that produces a permanent human-readable text of graphic document.
• Speakers - typically a pair of devices (2 channels) which convert electrical signals into audio.
  • Headphones - for a single user hearing the audio.
• Monitor - an electronic visual display with textual and graphical information from the computer.
  • CRT - (Cathode Ray Tube) display
  • LCD - (Liquid Crystal Display) as of 2010, it is the primary visual display for personal computers.
  • LED - (light-emitting diode) display
  • OLED - Organic Light-Emitting Diode

Sound card

Sound card

Main article: Sound card

Enables the computer to output sound to audio devices, as well as accept input from a microphone. Most modern computers have sound cards built-in to the motherboard, though it is common for a user to install a separate sound card as an upgrade. Most sound cards, either built-in or added, have surround sound capabilities.

Secondary storage

Secondary storage

Hardware that keeps data inside the computer for later use and remains persistent even when the computer has no power.

• Hard disk - for medium-term storage of data.
• Solid-state drive - a device similar to hard disk, but containing no moving parts and stores data in a digital format.
• RAID array controller - a device to manage several internal or external hard disks and optionally some peripherals in order to achieve performance or reliability improvement in what is called a RAID array.