Friday, August 14, 2015

KNOW COMPUTER HARDWARE Part 7

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Computer case

From Wikipedia, the free encyclopedia
 A computer case also known as a computer chassis, tower, system unit, cabinet, base unit or simply case and sometimes incorrectly referred to as the "CPU" or "hard drive",[1][2] is the enclosure that contains most of the components of a computer (usually excluding the display, keyboard and mouse).
Cases are usually constructed from steel (often SECC — Steel, electrogalvanized, cold-rolled, coil) or aluminium. Plastic is sometimes used, and other materials such as glass, wood and even Lego blocks have appeared in home-built cases.

 

Sizes

Further information: Comparison of computer form factors
Cases can come in many different sizes (known as form factors). The size and shape of a computer case is usually determined by the form factor of the motherboard, since it is the largest component of most computers. Consequently, personal computer form factors typically specify only the internal dimensions and layout of the case. Form factors for rack-mounted and blade servers may include precise external dimensions as well, since these cases must themselves fit in specific enclosures.
For example, a case designed for an ATX motherboard and power supply may take on several external forms, such as a vertical tower (designed to sit on the floor, height > width) or a flat desktop (height < width) or pizza box (height ≤ 5 cm (2 in), designed to sit on the desk under the computer's monitor). Full-size tower cases are typically larger in volume than desktop cases, with more room for drive bays and expansion slots. Desktop cases—and mini-tower cases under about 46 cm (18 in) high—are popular in business environments where space is at a premium.[3]
Currently, the most popular form factor for desktop computers is ATX, although microATX and small form factors have also become very popular for a variety of uses. In the high-end segment the unofficial and loosely defined XL-ATX spec appeared around 2009. XL-ATX extends the length of the Mainboard to accommodate 4 graphics cards with dual-slot coolers. Some XL-ATX mainboards increase the Mainboard's width as well, to allow more space for the CPU and Memory PWM, and in some cases a second CPU socket. While the market share of these exotic high-end mainboards is very low, almost all high-end cases and many mainstream cases support XL-ATX (10 expansion slots). Companies like In Win Development, Shuttle Inc. and AOpen originally popularized small cases, for which FlexATX was the most common[dubious – discuss] motherboard size. As of 2010 Mini ITX has widely replaced FlexATX as the most common small form factor Mainboard standard. The latest mini ITX mainboards from Asus, Gigabyte, Zotac and Foxconn offer the same feature set as full size mainboards. High-end mini ITX mainboards support standard desktop CPUs, use standard memory DIMM sockets and feature a full size pciE 16x slot with support for the fastest graphics cards. This allows customers to build a fully fledged high-end computer in a significantly smaller case. Apple Inc. has also produced the Mac Mini computer, which is similar in size to a standard CD-ROM drive.
Tower cases are often categorized as mini-tower, mid-tower or full-tower. Full tower cases are typically 56 cm (22 in) or more in height and intended to stand on the floor. They have anywhere from six to ten externally accessible drive bays. The ratio of external to internal bays is shifting, however, as computing technology moves from floppy disks and CD-ROMs to large capacity hard drives, USB flash drives, and network-based solutions. The full tower case was developed to house file servers which would typically be tasked with serving data from expensive CD-ROM databases which held more data than the hard drives commonly available. Hence many full tower cases include locking doors and other physical security features to prevent theft of the discs. Midtower cases are smaller, about 46 cm (18 in) high with two to four external bays. A minitower case will typically have only one or two external bays and stand from 36 cm (14 in) to 41 cm (16 in) tall. In 2012 CoolerMaster introduced the Cosmos II "ULTRA-Tower" case, standing 71 cm (28 in) tall and featuring 16 drive bays.[4][5] This is a high-end case intended for desktop systems and doesn't include security features.

Layout

Computer cases usually include sheet metal enclosures for a power supply unit and drive bays, as well as a rear panel that can accommodate peripheral connectors protruding from the motherboard and expansion slots. Most cases also have a power button or switch, a reset button, and LEDs to indicate power status as well as hard drive[citation needed] and network activity (in some models). Some cases include built-in I/O ports (such as USB and headphone ports) on the front of the case. Such a case will also include the wires needed to connect these ports, switches and indicators to the motherboard.

Major component locations

  • The motherboard is usually screwed to the case along its largest face, which could be the bottom or the side of the case depending on the form factor and orientation.
  • Form factors such as ATX provide a back panel with cut-out holes to expose I/O ports provided by integrated peripherals, as well as expansion slots which may optionally expose additional ports provided by expansion cards.
  • The power supply unit mounting point differs from case to case, but the most commonly used locations (both at the rear of the case) and their benefits/disadvantages are:
1. The top of the case, usually allowing the PSU's built-in fan to act as an auxiliary exhaust fan, but causes the PSU to be fed air heated by the internal components of the case, thus causing PSU efficiency and lifespan degradation.
2. The bottom of the case, with a (often filtered) vent in the bottom of the case allowing the PSU to draw cool air from the outside. Regardless of the mounting position, the PSU will usually be attached to the case with four screws to support its weight.
  • Most cases include drive bays on the front of the case; a typical ATX case includes both 5.25" and 3.5" bays. In modern computers, the former are used mainly for optical drives, while the latter are used for hard drives, floppy drives, and card readers.
  • Buttons and LEDs are typically located on the front of the case; some cases include additional I/O ports, temperature and processor speed monitors in the same area.
  • Vents are often found on the front, back, top, left side panel, and sometimes on the right side panel of the case. Regardless of their placement, their purpose is either to let cool air into the case, or to let hot air out. Larger vents usually allow cooling fans to be mounted via surrounding threaded screw holes. Newer cases include mountings for larger 120mm or 240mm cooling fans for quieter operation than the 80mm fans formerly common.

Internal access

Accessing the interior components of a modern tower case is done by removing the left side panel. Looking front-to-back, accessing the motherboard, PSU, drive bays and most case fan installation points is done by removing the left side panel. Removing the right side panel is done less often to access the space behind the motherboard mounting plate. This space is devoted to cable management, as cables routed in front of the motherboard will cause disruptions in the flow of air within the case.
Alternatively, the case may have a single large U-shaped cover that saddles the chassis.
To prevent the buildup of performance-degrading dust within the case, many models feature dust filters in front of the air intake fans. While the exact method of accessing the front filters depends on the case model, it usually requires the removal of the entire front panel. Removal of the front panel itself may or may not require the removal of one or both of the side panel. If there is any doubt, consult the user's manual if possible.
Traditionally, most computer cases required computer case screws to hold components and panels in place (i.e. motherboard, PSU, drives, and expansion cards). From the 2000s there is a trend towards tool-less cases, in which components are held together with snap-in plastic rails, thumbscrews, and other methods that do not require tools; this facilitates quick assembly and modification of computer hardware, and is also cheaper to manufacture.

Appearance

Further information: Case modding
Through the 1990s, most computer cases had simple rectangular shapes, and were often painted beige or white with little attention given to visual design. Beige box designs are still found on a large number of budget computers assembled from generic components. This class of machines is still known as white box computers.
Case modding is the artistic styling of computer cases, often to draw attention to the use of advanced or unusual components. Since the early 2000s, some cases have included clear side panels or acrylic windows so that users can look inside while it is operating. Modded cases may also include internal lighting, custom paint, or liquid cooling systems. Some hobbyists build custom cases from raw materials like aluminum, steel, styrofoam, acrylic, or wood.

Case manufacturers

See also: List of computer hardware manufacturers § Computer cases
Prominent after-market case manufacturers include Antec, BitFenix, Cooler Master, Corsair, Fractal Design, In Win Development, Lian Li, NZXT Corp., Raidmax, Rosewill, and Thermaltake.

Intrusion detection

Some computer cases include a biased switch (push-button) which connects to the motherboard. When the case is opened, the switch position changes and the system records this change. The system's firmware or BIOS may be configured to report this event the next time it is powered on.
This physical intrusion detection system may help computer owners detect tampering with their computer. However, most such systems are quite simple in construction; a knowledgeable intruder can open the case or modify its contents without triggering the switch.
In the past, many tower cases intended to house file servers featured a locking door covering the external drive bays. This was a security feature intended to prevent the theft of the CD-ROM discs the drives would be holding. At the time, CD-ROM capacity was larger than the hard disks available, and many business-critical databases were distributed on this media. These databases were often very expensive or held proprietary data, and hence would be likely targets for casual theft.

Gallery

  • Computer cases
  • SWTPC 6800 case with SS-50 and SS-30 buses—an early hobbyist machine
  • Cooler Master 690 II Advanced Nvidia Edition mid tower case
  • A beige mini tower case (microATX form factor)
  • Micro ATX Desktop case beside standard ATX tower case
  • Enthusiast case featuring translucent panel casemod
  • NZXT Case showing an example of a modern Enthusiast case along with Power supplies and a CPU Fan.
  • Three of the Wikimedia servers in 1U rackmount cases
  • Antec Fusion V2 home theater PC case with VFD display, volume control and some ports on front.
  • 8-slot Baby AT form factor case
  • Mac Pro tower case. Note the two barely visible front intake fans.
  • Power Mac tower case.
  • NeXT Cube
  • SGI Indigo tower case
  • SGI O2 tower case
  • IBM Personal Computer 5150 bare 5-slot case
  • IBM Personal Computer/AT
  • IBM Personal System/2 Model 55SX
  • IBM Personal System/2 Model 70
  • IBM Personal System/2 Model 70
  • IBM Personal System/2





KNOW COMPUTER HARDWARE Part 6

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Removable media   

From Wikipedia, the free encyclopedia

 

In computer storage, some types of removable media are designed to be read to or written to by removable readers, writers and drives.
Examples include:
Some removable media readers and drives are integrated into computers, others are themselves removable.
Removable media may also refer to some removable storage devices, when they are used to transport or store data. Examples include:

KNOW COMPUTER HARDWARE Part 5

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Output device

 From Wikipedia, the free encyclopedia

 An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) which converts the electronically generated information into human-readable form.

 

Display devices

A display device is an output device that visually conveys text, graphics, and video information. Information shown on a display device is called soft copy because the information exists electronically and is displayed for a temporary period of time. Display devices include CRT monitors, LCD monitors and displays, gas plasma monitors, and televisions.[3]

Input/output

CPT Hardware-InputOutput
Inputs are the signals or data received by the system, and outputs are the signals or data sent from it.
There are many input and output devices such as multifunction printers and computer-based navigation systems that are used for specialised or unique applications.[1] In computing, input/output refers to the communication between an information processing system (such as a computer), and the outside world. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it.

Types of output

Some types of output are text, graphics, tactile,[4] audio, and video. Text consists of characters (letters, numbers, punctuation marks, or any other symbol requiring one byte of computer storage space) that are used to create words, sentences, and paragraphs. Graphics are digital representations of nontext information such as drawings, charts, photographs, and animation (a series of still images in rapid sequence that gives the illusion of motion). Tactile output such as raised line drawings may be useful for some individuals who are blind. Audio is music, speech, or any other sound. Video consists of images played back at speeds to provide the appearance of full motion.[3]

Graphics (Visual)

Graphical output displayed on a screen.
A digital image is a numeric representation of an image stored on a computer. They don't have any physical size until they are displayed on a screen or printed on paper. Until that point, they are just a collection of numbers on the computer's hard drive that describe the individual elements of a picture and how they are arranged.[5] Some computers come with built-in graphics capability. Others need a device, called a graphics card or graphics adapter board, that has to be added.[6] Unless a computer has graphics capability built into the motherboard, that translation takes place on the graphics card.[7] Depending on whether the image resolution is fixed, it may be of vector or raster type. Without qualifications, the term "digital image" usually refers to raster images also called bitmap images. Raster images that are composed of pixels and is suited for photo-realistic images. Vector images which are composed of lines and co-ordinates rather than dots and is more suited to line art, graphs or fonts.[5] To make a 3-D image, the graphics card first creates a wire frame out of straight lines. Then, it rasterizes the image (fills in the remaining pixels). It also adds lighting, texture and color.[7]

Tactile

Haptic technology, or haptics, is a tactile feedback technology which takes advantage of the sense of touch by applying forces, vibrations, or motions to the user.[8] Several printers and wax jet printers have the capability of producing raised line drawings. There are also handheld devices that use an array of vibrating pins to present a tactile outline of the characters or text under the viewing window of the device.[4]

Audio

Speech output systems can be used to read screen text to computer users. Special software programs called screen readers attempt to identify and interpret what is being displayed on the screen[9] and speech synthesizers convert data to vocalized sounds or text.[6]

Smell

See Digital scent technology.

Examples

These examples of output devices also include input/output devices.[10][11] Printers and visual displays are the most common type of output device for interfacing to people, but voice is becoming increasingly available.[12]

 

KNOW COMPUTER HARDWARE Part 4

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Input device

 n computing, an input device is a peripheral (piece of computer hardware equipment) used to provide data and control signals to an information processing system such as a computer or information appliance. Examples of input devices include keyboards, mice, scanners, digital cameras and joysticks.

Many input devices can be classified according to:
  • modality of input (e.g. mechanical motion, audio, visual, etc.)
  • whether the input is discrete (e.g. key presses) or continuous (e.g. a mouse's position, though digitized into a discrete quantity, is fast enough to be considered continuous)
  • the number of degrees of freedom involved (e.g. two-dimensional traditional mice, or three-dimensional navigators designed for CAD applications)
Pointing devices, which are input devices used to specify a position in space, can further be classified according to:
  • Whether the input is direct or indirect. With direct input, the input space coincides with the display space, i.e. pointing is done in the space where visual feedback or the pointer appears. Touchscreens and light pens involve direct input. Examples involving indirect input include the mouse and trackball.
  • Whether the positional information is absolute (e.g. on a touch screen) or relative (e.g. with a mouse that can be lifted and repositioned)
Direct input is almost necessarily absolute, but indirect input may be either absolute or relative.[clarification needed] For example, digitizing graphics tablets that do not have an embedded screen involve indirect input and sense absolute positions and are often run in an absolute input mode, but they may also be set up to simulate a relative input mode like that of a touchpad, where the stylus or puck can be lifted and repositioned.

Keyboards

Main article: Computer keyboard
A 'keyboard' is a human interface device which is represented as a layout of buttons. Each button, or key, can be used to either input a linguistic character to a computer, or to call upon a particular function of the computer. They act as the main text entry interface for most users. Traditional keyboards use spring-based buttons, though newer variations employ virtual keys, or even projected keyboards. It is typewriter like device composed of a matrix of switches.
Examples of types of keyboards include:

Pointing

A computer mouse
Pointing devices are the most commonly used input devices today. A pointing device is any human interface device that allows a user to input spatial data to a computer. In the case of mice and touchpads, this is usually achieved by detecting movement across a physical surface. Analog devices, such as 3D mice, joysticks, or pointing sticks, function by reporting their angle of deflection. Movements of the pointing device are echoed on the screen by movements of the pointer, creating a simple, intuitive way to navigate a computer's graphical user interface (GUI).

High-degree of freedom input devices

Some devices allow many continuous degrees of freedom as input. These can be used as pointing devices, but are generally used in ways that don't involve pointing to a location in space, such as the control of a camera angle while in 3D applications. These kinds of devices are typically used in virtual reality systems (CAVEs), where input that registers six degrees of freedom is required.

Composite devices

Wii Remote with attached strap
Input devices, such as buttons and joysticks, can be combined on a single physical device that could be thought of as a composite device. Many gaming devices have controllers like this. Technically mice are composite devices, as they both track movement and provide buttons for clicking, but composite devices are generally considered to have more than two different forms of input.

Imaging and input devices

Microsoft Kinect sensor seen here on a TV, works by detecting human motion visually
Video input devices are used to digitize images or video from the outside world into the computer. The information can be stored in a multitude of formats depending on the user's requirement.
Medical Imaging

Audio input devices

Audio input devices are used to capture sound. In some cases, an audio output device can be used as an input device, in order to capture produced sound.

Punched Card devices

See Punched card input/output.

Other



 source:wikipedia


KNOW COMPUTER HARDWARE Part 3

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Expansion cards

Main article: Expansion card
An expansion card in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard or backplane to add functionality to a computer system via the expansion bus. Expansions cards can be used to obtain or expand on features not offered by the motherboard.

Storage devices

Main article: Computer data storage
Computer data storage, often called storage or memory, refers to computer components and recording media that retain digital data. Data storage is a core function and fundamental component of computers. The price of solid-state drives (SSD), which store data on flash memory, has dropped a lot in recent years, making them a better choice than ever to add to a computer to make booting up and accessing files faster.[8]
Fixed media
Data is stored by a computer using a variety of media. Hard disk drives are found in virtually all older computers, due to their high capacity and low cost, but solid-state drives are faster and more power efficient, although currently more expensive than hard drives, so are often found in more expensive computers. Some systems may use a disk array controller for greater performance or reliability.
Removable media
To transfer data between computers, a USB flash drive or Optical disc may be used. Their usefulness depends on being readable by other systems; the majority of machines have an optical disk drive, and virtually all have a USB port.

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
Input devices allow the user to enter information into the system, or control its operation. Most personal computers have a mouse and keyboard, but laptop systems typically use a touchpad instead of a mouse. Other input devices include webcams, microphones, joysticks, and image scanners.
Output device
Output devices display information in a human readable form. Such devices could include printers, speakers, monitors or a Braille embosser.

Wednesday, August 5, 2015

KNOW COMPUTER HARDWARE Part 2.

Posted on 6:34 AM by MarinoBlogs with No comments

Case

Main article: Computer case
The computer case is a plastic or metal enclosure that houses most of the components. Those found on desktop computers are usually small enough to fit under a desk, however in recent years more compact designs have become more common place, such as the all-in-one style designs from Apple, namely the iMac. Though a case can basically be big or small, what matters more is which form factor of motherboard it’s designed for.[6] Laptops are computers that usually come in a clamshell form factor, again however in more recent years deviations from this form factor have started to emerge such as laptops that have a detachable screen that become tablet computers in their own right.

Power supply

Main article: Power supply unit (computer)
A power supply unit (PSU) converts alternating current (AC) electric power to low-voltage DC power for the internal components of the computer. Laptops are capable of running from a built-in battery, normally for a period of hours.[7]

Motherboard

Main article: Motherboard
The motherboard is the main component of a computer. It is a large rectangular board with integrated circuitry that connects the other 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 or part of the motherboard include:

  • The CPU (Central Processing Unit) 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. Most newer CPUs include an on-die Graphics Processing Unit (GPU).
  • The Chipset, which includes the north bridge, mediates communication between the CPU and the other components of the system, including main memory.
  • The Random-Access Memory (RAM) stores the code and data that are being actively accessed by the CPU.
  • The Read-Only Memory (ROM) stores the BIOS that runs when the computer is powered on or otherwise begins execution, a process known as Bootstrapping, or "booting" or "booting up". The BIOS (Basic Input Output System) includes boot firmware and power management firmware. Newer motherboards use Unified Extensible Firmware Interface (UEFI) instead of BIOS.
  • Buses connect the CPU to various internal components and to expand cards for graphics and sound.
  • The CMOS battery is also attached to the motherboard. This battery is the same as a watch battery or a battery for a remote to a car's central locking system. Most batteries are CR2032, which powers the memory for date and time in the BIOS chip.





KNOW COMPUTER HARDWARE Part 1.

Posted on 6:22 AM by MarinoBlogs with No comments
Computer hardware (usually simply called hardware when a computing context is implicit) is the collection of physical elements that constitutes a computer system. Computer hardware is the physical parts or components of a computer, such as the monitor, mouse, keyboard, computer data storage, hard disk drive (HDD), system unit (graphic cards, sound cards, memory, motherboard and chips), and so on, all of which are physical objects that can be touched (that is, they are tangible).[1] In contrast, software is instructions that can be stored and run by hardware.

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