Personal Computer is a system, consisting of many components. Some of those components, like Windows XP, and all other programs, are software. The stuff we can actually see and touch is hardware.
A common hardware consists of a case or chassis in a tower shape (desktop) and the following parts:
Motherboard, PCI Buses, Graphics Card, Power Supply, Hard Drive, Computer Fan, CD/DVD Drives, etc.
Not everyone has exactly the same hardware. But those of you who have a desktop system, like the example shown in figure below, probably have most of the components.
A motherboard is the physical arrangement in a computer that contains the computer's basic circuitry and components. On the typical motherboard, the circuitry is imprinted or affixed to the surface of a firm planar surface and usually manufactured in a single step. The most common motherboard design in desktop computers today is the AT, based on the IBM AT motherboard. A more recent motherboard specification, ATX, improves on the AT design.
The motherboard is the "heart" of the computer, through which all other components interface.
On most PCs, it is possible to add memory chips directly to the motherboard. You may also be able to upgrade to a faster PC by replacing the CPU chip. To add additional core features, you may need to replace the motherboard entirely.
Different motherboards support different components, and so it is vital you make a number of decisions concerning general system specifications before you can pick the right motherboard.
The first important differential is which CPU the board supports. Two of the biggest makes of CPUs at the moment are Intel and AMD, yet you cannot buy motherboards that support the use of either: it will support one or the other, due to physical differences in the connectors. This is often referred to as a type of platform; for example, an ‘Intel platform motherboard' means a motherboard with an Intel CPU. Furthermore, you must choose a specific type of processor; for example, an AMD Athlon 64 or Pentium 4. Therefore, you must choose which CPU you want before you can choose your motherboard. Both Intel and AMD processors are capable of running the same applications, but there are differences in price and performance depending on which one you choose. Motherboard has the following components.
Central processing unit (CPU) - Performs most of the calculations which enable a computer to function, sometimes referred to as the "brain" of the computer. It processes everything from basic instructions to complex functions. Any time something needs to be computed, it gets sent to the CPU. Every day, it's compute this, compute that -- you'd think the CPU would need a break after awhile. But no -- it just keeps on processing. The CPU can also be referred to simply as the "processor."
Computer fan - Used to lower the temperature of the computer; a fan is almost always attached to the CPU, and the computer case will generally have several fans to maintain a constant airflow. Liquid cooling can also be used to cool a computer, though it focuses more on individual parts rather than the overall temperature inside the chassis.
A CPU cache is a cache used by the central processing unit of a computer to reduce the average time to access memory. The cache is a smaller, faster memory which stores copies of the data from the most frequently used main memory locations. As long as most memory accesses are to cached memory locations, the average latency of memory accesses will be closer to the cache latency than to the latency of main memory.
Random Access Memory (RAM) - Fast-access memory that is cleared when the computer is powered-down. RAM attaches directly to the motherboard, and is used to store programs that are currently running. It is the area where your computer stores programs that you are currently running and data that you are currently working on. RAM can be contrasted with disk storage. Disk storage holds all of your programs and all of your data -- whether you are working with them or not. When you turn off your computer, the contents of RAM instantly disappear, but the contents of your disk storage remain unharmed.
Read Only Memory (ROM) are memory chips which have had information stored on them which cannot be changed.
Firmware, a combination of software and hardware, is loaded from ROM run from the Basic Input-Output System (BIOS) or in newer systems.
Computer chips that have data or programs recorded on them are firmware. These chips commonly include the following: ROMs, PROMs (programmable read-only memory), and EPROMs (erasable programmable read-only memory). Firmware in PROM or EPROM is designed to be updated if necessary through a software update. Not every product has a firmware update. Sometimes an update is installed at the factory.
External Bus Controllers - used to connect to external peripherals, such as printers and input devices. These ports may also be based upon expansion cards, attached to the internal buses.
Parallel port - A parallel interface for connecting an external device such as a printer. Most personal computers have both a parallel port and at least one serial port. On PCs, the parallel port uses a 25-pin connector (type DB-25) and is used to connect printers, computers and other devices that need relatively high bandwidth. It is often called a Centronics interface after the company that designed the original standard for parallel communication between a computer and printer. (The modern parallel interface is based on a design by Epson.) A newer type of parallel port, which supports the same connectors as the Centronics interface, is the EPP (Enhanced Parallel Port) or ECP (Extended Capabilities Port). Both of these parallel ports support bi-directional communication and transfer rates ten times as fast as the Centronics port. Macintoshes have a SCSI port, which is parallel, but more flexible.
Serial port - A port, or interface, that can be used for serial communication, in which only 1 bit is transmitted at a time. Most serial ports on personal computers conform to the RS-232C or RS-422 standards. A serial port is a general-purpose interface that can be used for almost any type of device, including modems, mice, and printers (although most printers are connected to a parallel port).
USB - Universal Serial Bus (USB) makes connecting devices to your computer faster, easier and virtually limitless. High-speed USB devices are capable of communicating at speeds up to 12 megabits per second. USB makes Plug-and-Play a reality. Simply plug a USB device to your computer- without shutting down and without having to open your computer. Connect up to 127 printers, modems, keyboards, mice, joysticks, scanners, digital cameras, and other USB devices.
Firewire - Also known as IEEE 1394 and i.Link, is a high speed serial bus developed by Texas Instruments and Apple computers in the mid 1990s. Firewire is compatible with more than 63 electronic and digital devices, which makes it a great choice for many people. Technically speaking, Firewire is a PC serial bus interface standard that offers isochronous data services and high-speed communications between digital devices. Basically, Firewire facilitates faster data transfer rates and usability across multiple devices. Firewire is similar to Universal Serial Bus (USB), but it has a higher data transfer capacity - up to 800 Mbps, compared to the USB's 480 Mbps. This makes it ideal for peripherals that require high-speed data transfer, such as digital camcorders, DVD players and digital audio equipment.
SCSI (On Servers and older machines)
PS/2 (For mice and keyboards, being phased out and replaced by USB.)
A case that holds a transformer, voltage control, and (usually) a cooling fan, and supplies power to run the rest of the computer, the most common types of power supplies are AT and BabyAT (old) but the standard for PC's actually are ATX and micro ATX
Controllers for hard disk, CD-ROM and other drives like internal Zip and Jaz conventionally for a PC are IDE/ATA; the controllers sit directly on the motherboard (on-board) or on expansion cards, such as a Disk array controller. IDE is usually integrated, unlike SCSI which is found in most servers. The floppy drive interface is a legacy MFM interface which is now slowly disappearing. All these interfaces are gradually being phased out to be replaced by SATA and SAS.
IDE (Intelligent Drive Electronics or Integrated Drive Electronics) interface is an interface for mass storage devices, in which the controller is integrated into the disk or CD-ROM drive.
ATA (Advanced Technology Attachment) is a disk drive implementation that integrates the controller on the disk drive itself. There are several versions of ATA, all developed by the Small Form Factor (SFF) Committee.
- ATA: Known also as IDE, supports one or two hard drives, a 16-bit interface and PIO modes 0, 1 and 2.
- ATA-2: Supports faster PIO modes (3 and 4) and multiword DMA modes (1 and 2). Also supports logical block addressing (LBA) and block transfers. ATA-2 is marketed as Fast ATA and Enhanced IDE (EIDE).
- ATA-3: Minor revision to ATA-2.
- Ultra-ATA: Also called Ultra-DMA, ATA-33, and DMA-33, supports multiword DMA mode 3 running at 33 MBps.
- ATA/66: A version of ATA proposed by Quantum Corporation, and supported by Intel, that doubles ATA's throughput to 66 MBps.
- ATA/100: An updated version of ATA/66 that increases data transfer rates to 100 MBps.
SCSI (small computer system interface) is a parallel interface standard used by Apple Macintosh computers, PCs, and many UNIX systems for attaching peripheral devices to computers. Nearly all Apple Macintosh computers, excluding only the earliest Macs and the recent iMac, come with a SCSI port for attaching devices such as disk drives and printers.
The following varieties of SCSI are currently implemented:
- SCSI-1: Uses an 8-bit bus, and supports data rates of 4 MBps
- SCSI-2: Same as SCSI-1, but uses a 50-pin connector instead of a 25-pin connector, and supports multiple devices. This is what most people mean when they refer to plain SCSI.
- Wide SCSI: Uses a wider cable (168 cable lines to 68 pins) to support 16-bit transfers.
- Fast SCSI: Uses an 8-bit bus, but doubles the clock rate to support data rates of 10 MBps.
- Fast Wide SCSI: Uses a 16-bit bus and supports data rates of 20 MBps.
- Ultra SCSI: Uses an 8-bit bus, and supports data rates of 20 MBps.
- SCSI-3: Uses a 16-bit bus and supports data rates of 40 MBps. Also called Ultra Wide SCSI.
- Ultra2 SCSI: Uses an 8-bit bus and supports data rates of 40 MBps.
- Wide Ultra2 SCSI: Uses a 16-bit bus and supports data rates of 80 MBps.
SATA (Serial Advanced Technology Attachment) is a computer bus primarily designed for transfer of data between a computer and mass storage devices such as hard disk drives and optical drives.
The main advantages over the older parallel ATA interface are faster data transfer, ability to remove or add devices while operating (hot swapping), thinner cables that let air cooling work more efficiently, and more reliable operation with tighter data integrity checks.
Produces the output for the computer display. This will either be built into the motherboard or attached in its own separate slot (PCI, PCI-E or AGP), in the form of a Graphics Card.
A graphics card is a peripheral device that enables the computer to process and deliver graphics, animation, and videos. A graphics card is also called a video card, video adapter, or display adapter.
It is a board that plugs into a personal computer to give it display capabilities. The display capabilities of a computer, however, depend on both the logical circuitry (provided in the video adapter) and the display monitor. A monochrome monitor, for example, cannot display colors no matter how powerful the video adapter.
Many different types of video adapters are available for PCs. Most conform to one of the video standards defined by IBM or VESA.
Each adapter offers several different video modes. The two basic categories of video modes are text and graphics. In text mode, a monitor can display only ASCII characters. In graphics mode, a monitor can display any bit-mapped image. Within the text and graphics modes, some monitors also offer a choice of resolutions. At lower resolutions a monitor can display more colors.
Modern video adapters contain memory, so that the computer's RAM is not used for storing displays. In addition, most adapters have their own graphics coprocessor for performing graphics calculations. These adapters are often called graphics accelerators.
CD - the most common type of removable media, inexpensive but has a short life-span.
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 - a popular type of removable media that is the same dimensions as a CD but stores up to 6 times as much information. It is the most common way of transferring digital video.
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 - a high-density optical disc format for the storage of digital information, including high-definition video.
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 high-density optical disc format and successor to the standard DVD. Currently
Floppy disk - an outdated storage device consisting of a thin disk of a flexible magnetic storage medium.
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.
Tape drive - a device that reads and writes data on a magnetic tape, usually used for long term storage.
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.
Connects the computer to the Internet and/or other computers.
Modem - for dial-up connections
Network card - for DSL/Cable internet, and/or connecting to other computers.
Direct Cable Connection - Use of a null modem, connecting two computers together using their serial ports or a Laplink Cable, connecting two computers together with their parallel ports.
Keyboard - a device, to input text and characters by depressing buttons (referred to as keys), similar to a typewriter. The most common English-language key layout is the QWERTY layout.
Pointing devices
Mouse - a pointing device that detects two dimensional motion relative to its supporting surface.
Trackball - a pointing device consisting of an exposed portruding ball housed in a socket that detects rotation about two axes.
Xbox 360 Controller - A controller used for XBOX 360, Which with the use of the application Switchblade(tm), Can be be used as an additional pointing device with the left or right thumbstick.
Gaming devices
Joystick - a general control device that consists of a handheld stick that pivots around one end, to detect angles in two or three dimensions.
Gamepad - a general game controller held in the hand 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.
Webcam - a low resolution 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 an electrical signal
