Hardware is a general term for the physical artifacts of a technology. It may also mean the physical components of a computer system, in the form of computer hardware.

Hardware historically meant the metal parts and fittings that were used to make wooden products stronger, more functional, longer lasting and easier to fabricate or assemble

Business Hardware

COMPUTER BASIC FUNCTION – ACCEPT DATA, STORE DATA AND INSTRUCTION, PROCESS DATA, OUTPUT DATA

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I/O - is the means by which a computer exchanges information with the outside world.[26] Devices that provide input or output to the computer are called peripherals. On a typical personal computer, peripherals include input devices like the keyboard and ouse, and output devices such as the display and printer. Hard disk drives, floppy disk drives and optical disc drives serve as both input and output devices. Computer networking is another form of I/O

CPU

CPU - The control unit (often called a control system or central controller) manages the computer's various components; it reads and interprets (decodes) the program instructions, transforming them into a series of control signals which activate other parts of the computer. Control systems in advanced computers may change the order of some instructions so as to improve performance.

Internal Memory

Internal Memory - Computer main memory comes in two principal varieties: random-access memory or RAM and read-only memory or ROM. RAM can be read and written to anytime the CPU commands it, but ROM is pre-loaded with data and software that never changes, so the CPU can only read from it. ROM is typically used to store the computer's initial start-up instructions. In general, the contents of RAM are erased when the power to the computer is turned off, but ROM retains its data indefinitely.

External Memory

External Memory - Flash memory blurs the distinction between ROM and RAM, as it retains its data when turned off but is also rewritable. It is typically much slower than conventional ROM and RAM however, so its use is restricted to applications where high speed is unnecessary

Supercomputers

Supercomputers - are used for highly calculation-intensive tasks such as problems involving quantum physics, weather forecasting, climate research, molecular modeling (computing the structures and properties of chemical compounds, biological macromolecules, polymers, and crystals), physical simulations (such as simulation of airplanes in wind tunnels, simulation of the detonation of nuclear weapons, and research into nuclear fusion)

Mainframe computers

Mainframe computers - have abilities not so much defined by their single task computational speed (usually defined as MIPS — Millions of Instructions Per Second) as by their redundant internal engineering and resulting high reliability and security, extensive input-output facilities, strict backward compatibility with older software, and high utilization rates to support massive throughput. These machines often run for years without interruption, with repairs and hardware upgrades taking place during normal operation.

Midrange computers

Midrange computers - are a class of computer systems which fall in between mainframe computers and microcomputers, computers of the comparable class are instead universally known as servers to recognize that they "serve" end users at their "client" computers

 Microcomputer - is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers. Many microcomputers (when equipped with a keyboard and screen for input and output) are also personal computers (in the generic sense).

Central Processing Unit or processor is the portion of a computer system that carries out the instructions of a computer program, and is the primary element carrying out the computer's functions.

 

ALU - The set of arithmetic operations that a particular ALU supports may be limited to adding and subtracting or might include multiplying or dividing, trigonometry functions (sine, cosine, etc) and square roots. Some can only operate on whole numbers (integers) whilst others use floating point to represent real numbers—albeit with limited precision.

MACHINE CYCLE

Machine cycle - (sometimes called fetch-and-execute cycle, fetch-decode-execute cycle,

or FDX) is the basic operation cycle of a computer. It is the process by which a computer retrieves a program instruction from its memory,

determines what actions the instruction requires, and carries out those actions. This cycle is

repeated continuously by the central processing unit (CPU), from boot up to when the computer is

shut down.

Word 

Word  - is a term for the natural unit of data used by a particular computer design. A word is simply a fixed sized group of bits that are handled together by the system.

Output Devices include all electronic and electromechanical devices that deliver result of computer processing

  CRT stands for cathode ray tube, describing

the technology inside an analog computer monitor or television set. A CRT monitor or TV is readily recognizable by its bulky form. LCD monitors and plasma television sets, or flat panel displays, use newer digital technologies.

The CRT monitor creates a picture out of many rows or lines of tiny colored dots. These are technically not the same thing as pixels, but the terms are often used interchangeably. The more lines of dots per inch, the higher and clearer the resolution. Therefore 1024 x 768 resolution will be sharper than 800 x 600 resolution because the former uses more lines creating a denser, more detailed picture. Higher resolutions are important for displaying the subtle detail of graphics. For text, resolution isn't as critical.

The CRT monitor creates a picture out of many rows or lines of tiny colored dots. These are technically not the same thing as pixels, but the terms are often used interchangeably. The more lines of dots per inch, the higher and clearer the resolution. Therefore 1024 x 768 resolution will be sharper than 800 x 600 resolution because the former uses more lines creating a denser, more detailed picture. Higher resolutions are important for displaying the subtle detail of graphics. For text, resolution isn't as critical.

A flat panel monitor can refer to either a computer or television monitor that does not use cathode ray tube (CRT) technology, but commonly LCD or plasma technology. This allows the monitor to have a thin profile, which is how the flat panel monitor gets its name. Because of its light weight, small footprint, clarity and digital technology, the flat panel monitor has become the monitor of choice.

Why would anyone want to switch to a lower resolution? In higher resolutions, images improve but they also become smaller. For instance, the icons on a desktop, toolbars within software, and menus within the operating system are all reduced at higher resolutions. Though many of these items can be adjusted up, some people prefer a lower resolution to get overall larger images on screen. This might be a particular concern for those with visual disabilities. In this case, one should carefully view the flat panel monitor prior to purchase to be sure the native resolution will be comfortable.

What is a Printers? A printer is an output device that prints

characters, symbols, and perhaps graphics on paper. The printed output is generally referred to as hardcopy because it is in relatively permanent form. Softcopy refers to temporary images such as those displayed on a monitor. Printers are categorized according to whether or not the image produced is formed by physical contact of the print mechanism with the paper. Impact printers have contact; nonimpact printers do not

Impact Printers An impact printer has mechanisms

resembling those of a typewriter. It forms characters or images by striking a mechanism such as a print hammer or wheel against an inked ribbon, leaving an image on paper. Impact printers are dying out; however, you may still come in contact with a dot-matrix printer. A dot-matrix printer contains a print head of small pins that strike an inked ribbon, forming characters or images.

Print heads are available with 9, 18, or 24 pins; the 24-pin head offers the best print quality. Dot-matrix printers permit a choice between output of draft quality; a coarser-looking 72 dots per inch vertically, which may be acceptable for drafts of papers and reports, and near-letter-quality, a crisper-looking 144 dots per inch vertically, which is more suitable for a finished product to be shown to other people.

Dot-matrix printers print about 40-300 characters per second (cps) and can print some graphics, although the reproduction quality is poor. Color ribbons are available for limited use of color. Dot-matrix printers are noisy, inexpensive, and they can print through multipart forms, creating several copies of a page at the same time, which ninimpact printers cannot do.

Another type of impact printer is not used with microcomputers. Large computer installations use high-speed line printers, which print a whole line of characters at once rather a single character at a time. Some, called chain printers, contain characters on a rotating chain; others, called band printers, contain characters on a rotation band. Speeds of up to 3000 lines a minute may be possible with these machines.

Non Impact Printer

Nonimpact printers, used almost everywhere now, are faster and quieter than

impact printers because they have fewer moving parts. Nonimpact printers form characters and images without direct physical contact between the printing

mechanism and the paper.

Two types of nonimpact printers often used with microcomputers are laser printers and

ink-jetprinters.

Laser Printer: Like a dot-matrix printer, a laser printer creates images with dots. However, as in a photocopying machine, these images are created on a drum, treated with a magnetically charged ink-like toner (powder), and then transferred from drum to paper.

- There are good reasons why laser printers are so popular. They produce sharp, crisp images of both text and graphics, providing resolutions from 300 dpi up to 1200 dpi, which is near-typeset quality (NTQ). They are quiet and fast. They can print 4-32 text-only pages per minute for individual microcomputers, and more than 120 pages per minute for mainframes.

(Pages with more graphics print more slowly.) They can print in many fonts (type styles and sizes). The more expensive models can print in different colors.

Laser printers have built-in RAM chips to store documents output from the computer. If you are working in desktop publishing and printing complicated documents with color and many graphics, you will need a printer with a lot of RAM. Laser printers also have their own ROM chips to store fonts and their own small dedicated processor. To be able to manage graphics and complex page design, a laser printer works with a page description language, a type of software that has become a standard for printing graphics on laser printers.

A PDL (page description language) is software that describes the shape and position of letters and graphics to the printer. PostScript, from Adobe Systems, is one common type of page description language; HPGL, Hewlett-Packard Graphic Language, is another

Non impact Printer

The printer comprises electrodes arrayed in circumferential rings and rows parallel to the axis of a cylinder. This axis corresponds to the vertical direction of characters printed on a sheet of paper. The print cylinder is moved in the direction of a line of print transversely to the direction of feed movement of the paper and rotates with respect to the paper in order to avoid sliding movement.

A movable inked ribbon is disposed against the top face of the paper on which the printing is to be effected, and on the opposite side to the print cylinder. The inked ribbon is electrically conducting and connected to one terminal of the power supply which selectively energizes the electrodes. The ribbon is moved in the same direction as the print cylinder by means of drive rollers. The inked ribbon passes through an inking station for continuously renewing the layer of ink.

The inked ribbon is also moved in the same direction as the paper by a face cam to ensure there is always a freshly inked band of the ribbon opposite the electrodes but this may not be necessary and is a feature omitted from a modified embodiment in which the ribbon rollers drive it in the direction of paper feed.

Impact Printer

Impact printers are the oldest print technologies still in active production. Some of the largest printer vendors continue to manufacture, market, and support impact printers, parts, and supplies. Impact printers are most functional in specialized environments where low-cost printing is essential. The three most common forms of impact printers are dot-matrix, daisy-wheel, and line printers.

Refers to a class of printers that work by banging a head or needle against an ink ribbon to make a mark on the paper. This includes dot-matrix printers, daisy-wheel printers, and line printers. In contrast, laser and ink-jet printers are nonimpact printers. The distinction is important because impact printers tend to be considerably noisier than nonimpact printers but are useful for multipart forms such as invoices.