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.
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
- Mouse - a pointing device that detects two dimensional motion relative to its supporting surface.
- 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.
Power supply
Main article: Power supply unit (computer)
Removable media devices
Main article: Computer storage
- CD (compact disc) - the most common type of removable media, suitable for music and data.
- CD-ROM Drive - a device used for reading data from a CD.
- CD Writer - a device used for both reading and writing data to and from a CD.
- DVD (digital versatile disc) - a popular type of removable media that is the same dimensions as a CD but stores up to 12 times as much information. It is the most common way of transferring digital video, and is popular for data storage.
- DVD-ROM Drive - a device used for reading data from a DVD.
- DVD Writer - a device used for both reading and writing data to and from a DVD.
- DVD-RAM Drive - a device used for rapid writing and reading of data from a special type of DVD.
- Blu-ray Disc - a high-density optical disc format for data and high-definition video. Can store 70 times as much information as a CD.
- BD-ROM Drive - a device used for reading data from a Blu-ray disc.
- BD Writer - a device used for both reading and writing data to and from a Blu-ray disc.
- HD DVD - a discontinued competitor to the Blu-ray format.
- Floppy disk - an outdated storage device consisting of a thin disk of a flexible magnetic storage medium. Used today mainly for loading RAID drivers.
- Iomega Zip drive - an outdated medium-capacity removable disk storage system, first introduced by Iomega in 1994.
- USB flash drive - a flash memory data storage device integrated with a USB interface, typically small, lightweight, removable, and rewritable. Capacities vary, from hundreds of megabytes (in the same ballpark as CDs) to tens of gigabytes (surpassing, at great expense, Blu-ray discs).
- Tape drive - a device that reads and writes data on a magnetic tape, used for long term storage and backups.
Motherboard
Main article: Motherboard
The motherboard is the main component inside the case. It is a large rectangular board with integrated circuitry that connects the rest of the parts of the computer including the CPU, the RAM, the disk drives (CD, DVD, hard disk, or any others) as well as any peripherals connected via the ports or the expansion slots.Components directly attached to the motherboard include:
- The central processing unit (CPU) performs most of the calculations which enable a computer to function, and is sometimes referred to as the "brain" of the computer. It is usually cooled by a heat sink and fan.
- The chip set mediates communication between the CPU and the other components of the system, including main memory.
- RAM (Random Access Memory) stores resident part of the current running OS (OS core and so on) and all running processes (applications parts, using CPU or input/output (I/O) channels or waiting for CPU or I/O channels).
- The BIOS includes boot firmware and power management. The Basic Input Output System tasks are handled by operating system drivers.
- Internal Buses connect the CPU to various internal components and to expansion cards for graphics and sound.
- Current
- The north bridge memory controller, for RAM and PCI Express
- PCI Express, for expansion cards such as graphics and physics processors, and high-end network interfaces
- PCI, for other expansion cards
- SATA, for disk drives
- ATA
- The north bridge memory controller, for RAM and PCI Express
- Obsolete
- Current
Personal computer hardware
A personal computer is made up of multiple physical components of computer hardware, upon which can be installed a system software called operating system and a multitude of software applications to perform the operator's desired functions.
Though a PC comes in many different forms, a typical personal computer consists of a case or chassis in a tower shape (desktop), containing components such as a motherboard.
Though a PC comes in many different forms, a typical personal computer consists of a case or chassis in a tower shape (desktop), containing components such as a motherboard.
Definition of RAM or Rom
Sunday 27 March 2011
Random-access memory (RAM) refers to a storage technology that allows you to read and write data as many times as needed. Contrast this to ROM which allows data to be written once after which it permits only reading.
RAM is typically erased when a computer is shut down, though some RAM chips maintain data indefinitely without electrical power. Technically, RAM devices are not limited to memory chips, and random-access memory as a storage format is not limited to use as working memory. In a broad sense, modern storage devices for long-term or secondary storage, including magnetic media and laser-readable CDs and DVDs, are forms of random-access memory.
Rom Read-only memory (ROM) refers to a storage technology that allows you to write data only once. After the data has been written, you can read it an unlimited number of times. Contrast this with random-access memory (RAM) that allows you to read and write data as many times as needed.
Originally, the term ROM referred to memory chips. However, with the creation of other stored devices, the term is being used more widely. In particular, CD-ROM is used to distinguish CDs that can only be read and not written too.
CPU (central processing unit)
The CPU (central processing unit) is the part of a computer controls the interpretation and execution of instructions. Generally, the CPU is a single microchip, but that doesn't necessarily have to be the case. In the consumer desktop and laptop market, the CPU market is dominated by Intel, AMD, and IBM. These manufacturers supply the computer makers such as Dell, HP, and Apple.
Due to its importance to every computing task, the speed of the CPU, usually measured in gigahertz (GHz) is the number that most vendors use in their marketing campaigns. In the past, the larger the number, the faster the computer could be expected to be. However, in recent years, the speed of the CPU has had less impact as other components of a computer take on more and more of the workload. Also, differences in technology mean that a slower chip that performs more calculations per cycle can actually be faster than a higher rate chip doing fewer calculations per cyc
Desktop CPU
Tower CPU
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