mobile devices

Definition:


A mobile device, which is also referred to as a handheld, handheld device or handheld computer, is a pint-sized computing device. Mobile devices usually come with a touch or non-touch display screen and sometimes, even a mini keyboard.


There are many types of mobile devices, the commonest among them being, mobile phones, smartphones, PDAs, pagers and Personal Navigation Devices.


PDAs and smartphones are among the most preferred mobile devices, which offer all the conveniences of a personal computer, along with a very small form factor. EDAs or Enterprise Digital Assistants are best for business users.


A mobile device (also known as a handheld device, handheld computer or simply handheld) is a small, handheld computing device, typically having a display screen with touch input and/or a miniature keyboard and weighing less than 2 pounds (0.91 kg). Apple, HTC, LG, Research in Motion (RIM) and Motorola Mobility are just a few examples of the many manufacturers that produce these types of devices.


A handheld computing device has an operating system (OS), and can run various types of application software, known as apps. Most handheld devices can also be equipped with Wi-Fi, Bluetooth, and GPS capabilities that can allow connections to the Internet and other Bluetooth-capable devices, such as an automobile or a microphone headset. A camera or media player feature for video or music files can also be typically found on these devices along with a stable battery power source such as a lithium battery.


Early pocket-sized ones were joined in the late 2000s by larger but otherwise similar tablet computers. Much like in a personal digital assistant (PDA), the input and output of modern mobile devices are often combined into a touch-screen interface.


Smartphones and PDAs are popular amongst those who wish to use some of the powers of a conventional computer in environments where carrying one would not be practical. Enterprise digital assistants can further extend the available functionality for the business user by offering integrated data capture devices like barcode, RFID andsmart card readers.






Example:




Samsung tab 10.1

#copypaste from http://en.wikipedia.org/wiki/Mobile_device and http://mobiledevices.about.com/od/glossary/g/What-Is-A-Mobile-Device.htm

output devices

An output device is any peripheral device that converts machine-readable information into people-readable form such as a monitor, printer, plotter and voice output device.

• Monitors
• Printers
• Plotters
• Voice Output Devices
• Modems

Computer Display (Monitors)

A computer display is also called a display screen or video display terminal (VDT). A monitor is a screen used to display the output. Images are represented on monitors by individual dots called pixels. A pixel is the smallest unit on the screen that can be turned on and off or made different shades. The density of the dots determines the clarity of the images, the resolution.

• Screen resolution: This is the degree of sharpness of a displayed character or image. The screen resolution is usually expressed as the number of columns by the number rows. A 1024x768 resolution means that it has 1024 dots in a line and 768 lines. A smaller screen looks sharper on the same resolution. Another measure of display resolution is a dot pitch.
• Interlaced/Non-interlaced: An interlaced technique refreshes the lines of the screen by exposing all odd lines first then all even lines next. A non-interlaced technology that is developed later refreshes all the lines on the screen form top to bottom. The non- interlaced method gives more stable video display than interlaced method. It also requires twice as much signal information as interlaced technology.

There are two forms of display: cathode-ray tubes (CRTs) and flat-panel display.Cathode Ray Tubes (CRT)

A CRT is a vacuum tube used as a display screen for a computer output device. Although the CRT means only a tube, it usually refers to all monitors. IBM and IBM compatible microcomputers operate two modes unlike Macintosh based entirely on graphics mode. They are a text mode and a graphics mode. Application programs switch computers into appropriate display mode.Monochrome Monitors

A monochrome monitor has two colors, one for foreground and the other for background. The colors can be white, amber or green on a dark (black) background. The monochrome monitors display both text and graphics modes.

Color Monitors

A color monitor is a display peripheral that displays more than two colors. Color monitors have been developed through the following paths.

• CGA: This stands for Color Graphics Adapter. It is a circuit board introduced by IBM and the first graphics standard for the IBM PC. With a CGA monitor, it is harder to read than with a monochrome monitor, because the CGA (320 X 200) has much fewer pixels than the monochrome monitor (640 X 350). It supports 4 colors.
• EGA: It stands for Enhanced Graphics Adapter. EGA is a video display standard that has a resolution of 640 by 350 pixels and supports 16 colors. EGA supports previous display modes and requires a new monitor.
• VGA: VGA stands for Video Graphics Array. This is a video display standard that provides medium to high resolution. In a text mode, the resolution of this board is 720 by 400 pixels. It supports 16 colors with a higher resolution of 640 by 480 pixels and 256 colors with 320 X 200 pixels.
• Super VGA: This is a very high resolution standard that displays up to 65,536 colors. Super VGA can support a 16.8 million colors at 800 by 600 pixels and 256 colors at 1024 by 768 pixels. A high-priced super VGA allows 1280 by 1024 pixels. Larger monitors (17" or 21" and larger) with a high resolution of 1600 by 1280 pixels are available. VESA (Video Electronics Standards Association) has set a standard for super VGA.

Flat Panel Displays

Portable computers such as a lap top use flat panel displays, because they are more compact and consume less power than CRTs. Portable computers use several kinds of flat panel screens:Liquid-Crystal Displays (LCDs)

A display technology that creates characters by means of reflected light and is commonly used in digital watches and laptop computers. LCDs replaced LEDs (light emitting diodes) because LCDs use less power. LCDs are difficult to read in a strong light, because they do not emit their own light. Portable computers wanted to have brighter and easier to read displays. Backlit LCDsare used for the purpose now.

• Backlit LCDs: This is a type of LCD display having its own light source provided from the back of the screen. The backlit makes the background brighter and clear, as a result the texts and images appear sharper. However, this still is much less clear than CRTs. Thus, better technology is needed.
• Active Matrix LCDs: This is an LCD display technique in which every dot on the screen has a transistor to control it more accurately. This uses a transistor for each monochrome or each red, green and blue dot. It provides better contrast, speeds up screen refresh and reduces motion smearing.

Electroluminescent (EL) Displays

A flat panel display technology that actively emits light at each pixel when it is electronic charged. This provides a sharp, clear image and wide viewing angle. The EL display type of flat panel is better than LCD.

Gas Plasma Displays

This is also called a gas panel or a plasma panel and is another flat screen technology. A plasma panel contains a grid of electrodes in a flat, gas filled panel. The image can persist for a long time without refreshing in this panel. The disadvantages of the gas plasma displays are that they must use AC power and cannot show sharp contrast.

Printers

A printer is an output device that produces a hard copy of data. The resolution of printer output is expressed as DPI. Printers can be classified into different types in several ways. First, the printers can be divided into three categories by the way they print.

• Serial Printers: Also called a character printer. Print a single character at a time. They are usually inexpensive and slow.
• Line Printers: Print a line at a time. They are expensive and very fast. Line printers use a band, a chain, etc.
• Page Printers: Also called a laser printer. Print a page at a time. They usually use a laser to produce page images. Quality is best. This is a little bit expensive, but the price of the personal laser printer is decreasing. The price range of the personal laser printer is around $400, today.

Second, printers can be classified into two forms according to the use of a hammer.

• Impact Printers: Hammer hits ribbons, papers or print head. Dot-matrix and daisy-wheel printers are the example. Noisy.
• Nonimpact Printers: They do not have the hammer and do not hit. An example is an ink-jet and laser printer.

Another classification can be made by the way they form characters.

• Bit-Mapped Printers: Images are formed from groups of dots and can be placed anywhere on the page. They have many printing options and good printing quality. They use PostScript as a standard language for instructing a microcomputer.
• Character-based Printers: Printer print characters into the lines and columns of a page. These printers use predefined set of characters and are restricted in position of characters.

Microcomputers use five kinds of printers. They are daisy wheel printers, chain printers, dot-matrix printers, ink-jet printers, and laser printers.Daisy-Wheel Printer

Daisy-Wheel is a printer mechanism that uses any kind of hub (wheel) having a set of spokes at the margin of the hub. The wheel can be removed to use a different character set. The end of each spoke is a raised image of a type character. When the wheel is turned and the required character is aligned to the print hammer, the character is then struck into a ribbon and onto a paper with the hammer.
Daisy-Wheel Printer prints typewriter-like very high quality characters. However, they are slower and less reliable than dot-matrix printers. Microcomputer users seldom use this printer, because the better dot-matrix printers and inexpensive laser printers are available today.

Chain Printer

A chain printer uses a printing mechanism that uses character typefaces linked together in a chain. The chain spins horizontally around a set of hammers aligned with each position. When the required character is in front of the selected print position, hammer in that position hits the paper into the ribbon against the character in the chain.
This printer is not commonly found around microcomputers, because it is a very expensive, high-speed machine designed originally for mainframes and minicomputers. Chain printers are very reliable and can speed up to 3000 lines per minute.

Dot-Matrix Printer

Dot-matrix printers are printers that write characters and form graphic images using one or two columns of tiny dots on a print head. The dot hammer moving serially across the paper strikes an inked-ribbon and creates images on paper.
Dot matrix printers are popular printers used with microcomputers, because the printers are highly reliable and inexpensive. They are used for tasks where a high-quality image is not essential. Many users, however, move from dot printers to laser printers, because the price of laser printers is falling down. Several kinds of dot matrix printers are available with print heads that have 7, 9, 18, or 24 pins.

Ink-Jet Printer

Ink-jet is a printer mechanism that sprays one or more color of ink at high speed onto the paper and produces high-quality printing. This printer also produces color printing as well as high-quality image. That is, ink-jet printers can be used for variety of color printing at a relatively low cost. Ink-jet printing has two methods: Continuous stream method and drop-on- demand method.

Laser Printer

A laser printer is a printer that uses the electrophotograpic method used in a copy machine. The printer uses a laser beam light source to create images on a photographic drum. Then the images on the drum are treated with a magnetically charged toner and then are transferred onto a paper. A heat source is usually applied to make the images adhere.
In 1984, Hewlett-Packard introduced the first desktop laser printer, called the LaserJet. The laser printer revolutionized personal computer printing and has spawned desktop publishing.
The laser printer produces high-resolution letters and graphics quality images, so it is adopted in applications requiring high-quality output. Although a high-priced color laser printer is also available in the market, a less expensive, desktop gray scale laser printer is widely used. Recently, the laser printer is gaining its market share dramatically, mainly because the lowered price and the quality.

#copypaste from http://home.olemiss.edu/~misbook/hm5.htm

input devices

An input device is a peripheral device that converts symbols that people understand into bits that computers can process. An input device includes a keyboard, a terminal, a touch screen, a mouse, a scanner, etc.
Keyboard Entry

In keyboard entry, a user types characters, numerics and special symbols using a keyboard. The input usually appears on a monitor. A keyboard entry might be the most common way to input data.Keyboards

A keyboard is a device used to encode data by key depression, which enters information into a system. The keyboard converts alphabets and numbers, and other special symbols into electrical signals that processor can understand and process. These signals are sent to the computer's CPU. There are three different layouts.

• QWERTY: This is a standard keyboard layout. QWERTY indicates the arrangement of the upper left corner six letters in the first row of the alphabetic keys.
• AZERTY: This is a keyboard layout that is similar to the QWERTY layout and some European countries use this keyboard. This layout is slightly modified from the QWERTY keyboard.
• Dvorak: This is another keyboard layout modified greatly from a standard layout. The keyboard is devised to increase typing speed by placing frequently used keys more naturally. In the past, mechanical jams were a problem in typing. Thus, the standard keyboard layout was designed to limit typing speed. Interesting, huh?

Direct Input Devices

Direct input is a data entry form that does not use a keyboard to input data. Today, more data and instructions are entered a CPU of microcomputers directly using direct input devices used to provide a more natural user interface. These entry devices reduce users' typing errors. While direct input is an advanced fourth generation data entry form, voice input (speech input) is the mode of next generation input technology. There are many forms of direct input devices:

• Mouse
• Touch screen
• Light Pen
• Graphics Tablet
• Scanner
• Bar-code readers
• Magnetic Entry
• Voice-Input Devices

Mouse

An object used as a pointing and drawing device. The mouse usually has a ball and buttons and is connected to the system unit through serial port. As a mouse is rolled across the flat desktop in any direction, it locates the pointer correspondingly on the screen. Then it issues commands using the selection buttons on the mouse. Many portable microcomputers such as lap-tops use track balls instead of mice.

Touch Screen

A touch screen is a monitor screen that allows users to interact with a computer system by touching an area of the display screen. The screen is covered with a clear plastic layer that has a matrix of cells. A user touches a graphic button that displays option on the screen. Touch screens are easy to use. Thus, many kiosks use touch screens as input forms.

Light Pen

A light pen is a light-sensitive pen-like device used by pointing it at the display surface. A user brings the light pen to the desired point on the screen and presses a button, causing it to identify the current location. It is used to select options from a menu or to draw images.

Digitizer Tablet

A digitizer tablet is also called a graphics tablet or just a digitizer. The digitizer is a drawing tablet used to sketch new images or trace old drawing or photograph. The user uses a pen-like device called acursor to draw images. Designers and architects usually use digitizers. Light pen and digitizer technologies are used for pen-based computing.

Scanner

A scanner is a device that reads spatial pattern such as images, graphics and texts, and then generates digital signals of that pattern. Converted digital data may be processed by a computer, stored in a disk, printed by a printer or displayed on a monitor. Scanners are commonly used to capture graphic images that can then be placed in a page or on any document.Scanners usually include optical character recognition (OCR) software so that scanners can read and capture texts directly through optical scanning.

Bar Code Readers

A bar code is a specialized code represented by sets of parallel bars of varying thickness and separation. This is used for fast identification of items with an optimal scanner. The optical scanner is called a bar code reader. The bar code reader is a photoelectric scanner that read the bar code.

Magnetic Data Entry

There are two technologies in magnetic data entry. A magnetic ink character recognition (MICR) technology reads iron oxide ink preprinted or encoded on checks, deposit slips or on documents. AnMICR reader electronically captures data, by first magnetizing the magnetic ink characters and then sensing the signal.
Another form of magnetic data entry is the magnetic stripe technology that makes computers read credit cards. The dark magnetic stripe on the back of credit cards is the iron oxide coating. A magnetic stripe reader reads this magnetic stripe.

Voice Input Devices

Voice input devices are also called speech- recognition devices or voice-recognition systems. This device uses a voice recognition technology that converts a user's speech into a digital code. Spoken words are first digitized and then matched against a dictionary of patterns previously stored in the computer.
Speaker-dependent systems should be trained by taking actual user's word sample before using, but speaker-independent systems can recognize only limited vocabularies. The advantage of the voice input systems is that they enable users to keep their hands free for other tasks.

#copypaste from http://home.olemiss.edu/~misbook/hm4.htm

communication devices

What are they?

Communication devices may be simple and designed just to enhance speech output, such as amplifiers. Or they may be more complex, such as communication aids or laptops using communication software, which are designed to augment independent speech for students with severe general mobility difficulties such as in cerebral palsy. A user of augmentative and alternative communication aids (AAC) works through a series of pictures, symbols and words to produce sentences of synthesised speech.


Mobile or adapted telephones can also help communication. A deaf student might use text messaging to confirm appointments or to receive information from you.


E-mail is one of the most effective methods for communicating information to students and has a valuable role in an inclusive policy.


Much of the equipment available to aid communication is electronic and uses synthesised speech. However non-electric boards or books that use pictures, symbols and words may also be used.
How are they used?


Speech amplification may be useful in students’ presentations, or to answer questions in large halls.


Communication aids, as specialist devices or as part of a laptop set up, can provide a student with total oral language support. Vocabulary can be adapted to suit chosen courses and even particular occasions, such as a viva voce, although this may involve specialist support.


Mobile technology, text messaging and e-mailing are relevant to the online support offered to students whether the course has distance learning elements, is based on an e-learning paradigm or involves face-to-face tuition.
Any issues to be aware of?


It may be easier to adapt a learning situation to support a quietly spoken student or one who has voice problems rather than set up special equipment. Amplification or the use of a microphone can help but some students feel embarrassed taking this action. A smaller room or a particular seating position may be all that is needed.


On average we speak at between 140–160 words per minute, whereas those using communication aids can manage around 12–50 words per minute. So allow extra time in question and answer sessions as well as for presentations.


Text tends to be more concise than face-to-face conversations, which also include a considerable amount of non-verbal information. Be aware that some meaning may be lost in SMS or e-mail and misunderstandings can occur.

#copypaste from http://www.open.ac.uk/inclusiveteaching/pages/inclusive-teaching/communication-devices.php

basic information about me just like the basic part of computer~ hukhuk

As this is my first experience involved in blogging so I have no much words to say...

My name is Nurul Zahrah. Means "cahaya bunga"... yeaahh bunga.... really related to my life.

Im the second one out of three siblings. Im in the middle.. The bunga that being surrounded by kumbang.. Not just kumbang but also my bonzer...my bodyguard... har har!

Im quite 'manja'.. I admit that~ I was born on March 23rd 1993. I live in Kuala Lumpur. Love chatting and laughing...hmmm the most important is im still single~ hehe Im mixed bloody Malay(dad)-Chinese(mom). Thats why i look like a chinese. Obviously my sepet eyes expressed who i am...

Okayy..till then. Salam~

#whoaaahhh im officially blogger now...hewhew