1.Cac tu viet tat

Dip : dots pen inch

Cda: computer aided design/assised

Lan: local are network:

Ptp: page dis cuption language

Lcd: liquid cuytal display

ADA: Americans with disabilities

OLD: printer command language

ORD: optical character recogtion

TDDS: Tellephong devices for the deaf

TTYs: Teletype writers

SMS : Short message service

Rpm: revolutions perminute

PDL: page doscuption languages

PCL: printer comment language

CPU: central processing Unit

Ram: random access memory

PC: reconal computer

PPm: pager perminuter

CTP: Computer to plate

2.

-graphics:designs and images used in magazines, books

-hight output puality:output quality, measured in dots oer inch

-precise mixing:a partical color within the colour spectrum

-to:an ink powder used inlaser printers and copier

-scale:set of character that can be resized  without introducing distortion

-barcode:a rectangular pattem of magnetic ink on an object so that its detail read by a computer system

-printingplate: surface that cames a reproduction of the image, from wich the pages are prited

-inter mediate:in-between,missle

Anti-virus software - A program that finds and removes viruses from a computer. 

Backup - A copy on floppy disk or tape of files on a PC's hard disk. A backup is used in case the hard disk file(s) are erased or damaged.

Bit, bytes - A bit is the smallest piece of information that computers use. For simplicity, a PC uses bits in groups of 8 called bytes (8 bits = 1 byte).

Boot, boot up, boot disk - You boot (or boot up) your computer when you switch it on and wait while it prepares itself. Instructions for startup are given to the computer from the boot disk, which is usually the hard disk.

Browser, to browse - A browser is a program like Netscape or Internet Explorer. You use it to view or browse the Internet.

Bug - A (small) defect or fault in a program.

Cache - A kind of memory used to make a computer work faster.

CD-ROM - A disk for storing computer information. It looks like an audio CD.

CPU - Central Processing Unit. This is a PC's heart or 'brains'.

DOS - Disk Operating System. The original system used for PCs. You type in commands instead of pointing and clicking.

Driver - A small program that tells a PC how a peripheral works.

Electronic mail (email, e-mail) - Messages sent from one computer to another. You can see email on the screen or print it out.

Floppy disk - A cheap, removable disk used for storing or transferring information. It is floppy (soft) because it is plastic. See hard disk.

Floppy drive - The device used to run a floppy disk (usually drive 'A'.)

Folder (directory) - A sub-division of a computer's hard disk into which you put files.

Font - A particular sort of lettering (on the screen or on paper). Arial is a font. Times New Roman is another.

Format - All hard disks and floppy disks have to be electronically prepared for use by a process called formatting. Hard disks are pre-formatted by the computer manufacturer. If you buy a floppy disk that is not pre-formatted, you format it yourself, using a program that comes with your PC.

Graphics card - The equipment inside a computer that creates the image on the screen.

Hard disk - The main disk inside a computer used for storing programs and information. It is hard because it is metal. See floppy disk.

Icon - A small image or picture on a computer screen that is a symbol for folders, disks, peripherals, programs etc.

Internet - International network of computers that you connect to by telephone line. Two popular services of the Internet are the World Wide Web and electronic mail.

Kb, Mb, Gb - Kilobytes, megabytes, gigabytes. Used to measure computer memory and storage.

Memory - Memory is for the temporary storing of information while a computer is being used. See RAM, ROM and Cache.

MHz - Megahertz. This describes the speed of computer equipment. The higher the MHz the better the performance.

Modem - Equipment connected to a computer for sending/receiving digital information by telephone line. You need a modem to connect to the Internet, to send electronic mail and to fax.

OCR - Optical Character Recognition. OCR lets a PC read a fax or scanned image and convert it to actual lettering.

Parallel port - A socket at the back of a computer for connecting external equipment or peripherals, especially printers.

PC card - A device that is the same size as a thick credit card, for plugging into a slot on notebook computers. You can buy memory, modems and hard disks as PC cards.

Peripheral - Any equipment that is connected externally to a computer. For example, printers, scanners and modems are peripherals.

Pixel - The image that you see on the screen is made of thousands of tiny dots, points or pixels.

Program Software that operates a PC and does various things, such as writing text (word-processing program), keeping accounts (accounts program) and drawing pictures (graphics program).

QWERTY - The first 6 letters on English-language keyboards are Q-W-E-R-T-Y. The first 6 letters on French-language keyboards are A-Z-E-R-T-Y.

RAM, ROM - Two types of memory. RAM (Random Access Memory) is the main memory used while the PC is working. RAM is temporary. ROM (Read Only Memory) is for information needed by the PC and cannot be changed.

Resolution - The number of dots or pixels per inch (sometimes per centimetre) used to create the screen image.

Scanner - Equipment for converting paper documents to electronic documents that can be used by a computer.

Serial port - Socket at the back of a PC for connecting peripherals.

Taskbar, Start button - Two areas of the screen in Windows 95. The taskbar, at the bottom of the screen, shows the programs in use. The start button, in the bottom left corner, is for opening new programs.

TFT - Thin Film Transistor, a type of high quality screen for notebook computers.

Virus - A small, unauthorized program that can damage a PC.

Windows - An operating system used by the majority of PCs. The current versions are Windows 98 and Windows NT.

World Wide Web, WWW, the Web - WWW are initials that stand for World Wide Web. The Web is one of the services available on the Internet. It lets you access millions of pages through a system of links. Because it is 'world-wide', it was originally called the World Wide Web or WWW.

WYSIWIG - 'What You See Is What You Get.' With a WYSIWIG program, if you print a document it looks the same on paper as it looks on the screen.

 1. write a paragraph about different types of printed ou leared

Printing is the final stage in creating a document. Since the results you can obtain with different types of printer will vary substantially.

about 7 types of printers the following : Dot-matrix, Inkjet, laser, thermal transfer, Imagesetters, platesetter, plotters.

-Dot-matrix printer use pins to print the dots required to shape a character. They can print text and graphic; however, they produce relatively low resolution output – 72 to 180 dots per inch (dpi). They are used to print multi-part form, self-copying paper and continuous-form labels. They are slower than laser printer (see below) but much cheaper.

- Inkjet printer operate by projecting small ink droplet onto paper to form the required image. Colour and hues are created by the precise mixing of cyan, magenta, yellow and black inks. Inkjets are fairly fast, quiet, and not as expensive as laser printer. Nevertheless, you can still expect high quality results because there are some inkjet printer on the market with a resolution of 2,400 dpi.

-Laser printers produce output at great speed and with a very high resolution of 1,200-2,400 dpi. They scan the image with a laser beam and transfer it to paper with a special ink powder called toner  AND They are constantly being improved.  however,it are still expensive for home users

- Thermal transfer printers are used to produce colour images by transferring a wax-based ink onto the paper. They are popular for printing bar codes, labels and medium-resolution graphics.

-Imagesetters produce very high-resolution output (up to 3,540 dpi) on paper or on the actual film for making the printing plates. In addition, they are extremely fast. Imagesetters are most often used in desktop publishing (dtp). Although they produce the highest quality output, they have one important disadvantage. however  they are too expensive for homes or small offices.

- platesetter used  In modern lithographic printing, image are created on a DTP computer and then output directly to the printing plates, without requiring film as an intermediate step.

Plotter use ink and fine pens help in a carriage to draw very detailed designs on paper. They are used for construction plans, engineering drawings and other technical illustrations. Nowadays, traditional plotters are being replaced with wide- format inkjet

3. write a paragraph about the assitive technologies for the blin

   To work effectively, most blind users need to have their computer adapted with technologies such as Braille, screen magnifiers, speech synthesis and Optical Character Recognition (OCR).

Braille keyboards have Braille lettering on keyboard overlay, allowing the blind user to easily identify each key. For output, there are printers, called Braille embossers, that produce tactile Braille symbols on both sides of a page at high speed.

For someone with limited but usable vision, a screen magnifier may be appropriate. This type of software can enlarge text and images appearing on the screen by up to 16 times.

A speech synthesis system is used to read aloud the work on the computer. It has a speech synthesizer, which produces the audio output, and a screen reader - the program which reads aloud text and menus from word processors, databases and the Web.

OCR uses a flatbed scanner and specialized OCR software to read printed material and send the text to the computer. The PC can then produce a copy of the text in Braille, a magnified copy, or a version that can be read aloud by a speech synthesis system.

4. write a paragraph about the assitive technology for the deaf people

Deaf computer users can overcomemany communition difficulties with the aid of visual alerts are eletronic  notetakes and textphones. Visal alerts are indicators that’s alert the deft user when they receive new mail or when thre is a system error. So instead of hearing a sound, the user is alerted by a blinking menu bar or by a message on the screen. Electronic notetakers use software that types a summy of what is said in meetings onto the computer screen

Textphones allow the deaf to types and read phone conversation. They are also called telephone devices for the day or teletypewriters. They can be used in combination with relay services, whole an operator says what the text user types and types what a voice phone: user says deaf people can also communicate SMS and instant messaging\

5.write a short paragraph to compare CDs and DVDs

CDs and DVDsAt first sight, a DVD is similar to a CD. Both discs are 120mm in diameter and 1.2 mm thick. They also both use a laser beam to read data. However, they are very different in internal structure and data capacity. In a DVD, the tracks are very close together, thus allowing more track. The pits in which data is stored are also smaller, so there are more pits per track. As a result, a CD can hold 650- 700MB, whereas a basic DVD can hold 4.7GB.In addition, a DVD can be double-side and dual layer, with a capacity of 17GB

CDs come in three different format: 

CD-ROMs (read-only memory) are read-only units, meaning you cannot change the data stored on them (for example, a dictionary or a game)

            CD-R (recordable) discs are write-once devices which let you duplicate music CDs and other data CDs

            CD-RW (rewritable) discs enable you to write onto them many times, just like a hard disk

DVDs also come in several formats:

            DVD-ROMs are used in DVD computer driver. They allow for data archiving as well as interactive content

            DVD-R or DVD+R can only be record on once

            DVD-RW or DVD+RW discs can erased and re-used many times. They are to back up data files and to record audio and video

The DVD drive used in computers is also called a DVD burner because it records information by burning via typically refer to a standalone unit which resembles a video cassette recorder. New DVD recorder can play all CD and DVD formats. There are also portable DVD player- handhelp devices which let you watch movies or TV, play game and listen to music, wherever you are. They come with a built-in DVD drive and widescreen LCD display. They usually support multi-format playback – that is, they can play many files formats, including DVD-video , DivX, CD audiodiscs, MP3 music and IPEG image

6.write a paragraph introducing the most populal OS minitiol in U13

-the wondows family – designed by microsoft and used on most PCs. Themost recent version is windows vista

-macos – created by apple and used on microsoft computer

-linux – a multi-user system, found on mainframes and workstations in corpotate installtions

-linux – open – source software developed under the GNU . Genearl punlic licence. This means anybody can copy its source code, change it and distribute it. It is used in computer, appliances small devices

-windows mobiles – used on most PDAs and smartphones (PDAs incorporating mobile phones)

-palm Os-used on paln handhelp devices

-RIM-used on black berry communication devices developed by reserch In media

-The symbion OS-used by some phone maked including nokia and siemens

UNIT8

Printing is the final stage in creating a document. Since the results you can obtain with different types of printer will vary substantially, here is a guide to help you decide which one is most suitable for your needs.

To begin with, you should take into account that printers vary in cost, speed, print quality, and other factor such as noise or printing method. Technology is evolving so quickly that there is always a printer for very application or need.

Dot-matrix printer use pins to print the dots required to shape a character. They can print text and graphic; however, they produce relatively low resolution output – 72 to 180 dots per inch (dpi). They are used to print multi-part form, self-copying paper and continuous-form labels. They are slower than laser printer (see below) but much cheaper.

Inkjet printer operate by projecting small ink droplet onto paper to form the required image. Colour and hues are created by the precise mixing of cyan, magenta, yellow and black inks. Inkjets are fairly fast, quiet, and not as expensive as laser printer. Nevertheless, you can still expect high quality results because there are some inkjet printer on the market with a resolution of 2,400 dpi.

Laser printers produce output at great speed and with a very high resolution of 1,200-2,400 dpi. They scan the image with a laser beam and transfer it to paper with a special ink powder called toner. They are constantly being improved. In terms of speed and image quality, laser printers are preferred by experts for various reason; for instance, they have a wider range of scalable fonts than inkjet, can emulate different language systems, and can produce high-quality graphics; however, they are still expensive for home users.

Thermal transfer printers are used to produce colour images by transferring a wax-based ink onto the paper. They are popular for printing bar codes, labels and medium-resolution graphics.

Imagesetters produce very high-resolution output (up to 3,540 dpi) on paper or on the actual film for making the printing plates. In addition, they are extremely fast. Imagesetters are most often used in desktop publishing (dtp). Although they produce the highest quality output, they have one important disadvantage: they are too expensive for homes or small offices.

In modern lithographic printing, image are created on a DTP computer and then output directly to the printing plates, without requiring film as an intermediate step. This technology is called computer to plate, or CTP, and the machine used is called a platesetter.

Finally, we have plotter. Plotter use ink and fine pens help in a carriage to draw very detailed designs on paper. They are used for construction plans, engineering drawings and other technical illustrations. Nowadays, traditional plotters are being replaced with wide- format inkjet

UNIT9

Computer have taken a dominant role in our society meaning most jobs now require access to computer and the Internet. But what happens if a person is blind, deaf or motor-disable? They needn’t worry. The latest assistive technology is designed to help them use computers and do their jobs in the office, learn at school, or interact with their families at home. In addition, new laws oblige companies to adapt the workplace to accommodate disable people. For example, the Americans with Disabilities Act (ADA) and the UK’s Disability Discrimination Act make it illegal for employers to discriminate against people with disabilities.

To work effectively, most blind users need to have their computer adapted with technologies such as Braille, screen magnifiers, speech synthesis and Optical Character Recognition (OCR).

Braille keyboards have Braille lettering on keyboard overlay, allowing the blind user to easily identify each key. For output, there are printers, called Braille embossers, that produce tactile Braille symbols on both sides of a page at high speed.

For someone with limited but usable vision, a screen magnifier may be appropriate. This type of software can enlarge text and images appearing on the screen by up to 16 times.

A speech synthesis system is used to read aloud the work on the computer. It has a speech synthesizer, which produces the audio output, and a screen reader - the program which reads aloud text and menus from word processors, databases and the Web.

OCR uses a flatbed scanner and specialized OCR software to read printed material and send the text to the computer. The PC can then produce a copy of the text in Braille, a magnified copy, or a version that can be read aloud by a speech synthesis system.

Deaf computer users can overcome many communication  difficulties with the aid of visual alerts, electronic notetakers and textphones. Visual alerts are indicators that alert the deaf user when they receive  new mail or when there is a system error. So instead of hearing a sound, the user is alerted by a blinking menu bar or by a message on the screen. Electronic notetakers use software that types a summary of what is said in meetings onto the computer screen.

Textphones allow the deaf to type and read phone conversations. They are also called TDDs (telephone Devices for the Deaf) or TTYs ( TeleTypewriters). They can be used in combination with relay services, where an operator says what the text user types, and types what a voice phone user says. Deaf people can also communicate via SMS and instant messaging.

Motor impaired workers unable to type on a standard key board can employ expanded or ergonomic keyboard, on-screen keyboards, adaptive switches and voice recognition system.

On-screen keyboards are software images of a keyboard that appear on the screen and may be activated with a trackball, touch screen, screen-pointing device, or eye movements. In an eyegaze system, the keys on the virtual keyboard are activated by the user’s eyes when they pause on a key for two or three seconds.

Switches come in many shapes and sizes. They are operated by muscle movements or breath control. For example, a pneumatic switch – known as a sip and puff – allows someone with quadriplegia to control the PC by puffing and sipping air through a pneumatic tube. People with quadriplegia can also use sip and puff joysticks.

Finally, there’s voice recognition, which allows the computer to interpret human speech, transforming the words into digitized text or instructions.

UNIT10

Magnetic storage

Magnetic storage devices store data by magnetizing particles on a disk or tape.

A floppy disk is so called because it consists of a flexible sheet of plastic, coated with iron oxide – a magnetizable material. A floppy disk drive spins at 360 revolution per minute (rpm), so it’s relatively slow. However, a hard drive spins at over 7,200 rpm and stores data on a stack of metal rotating disks called platters. This means you can store much more data and retrieve information much faster.

New disks need to be formatted before you can use them, unless they come preformatted from the manufacturer. When the disk is formatted the operating system (OS) organized the disk surface into circular tracks and divides each track into sectors. The OS creates a directory which will record the specific location of files. When you save file, the OS moves the read/write head of the drive towards empty sectors, record the data and writes an entry for the directory. Later on, when you open that file, the OS looks for its entry in the directory, move the read/write heads to the correct sector, and reads the file in the RAM area. However, formatting erases any existing files on a disk, so do not want to lose is stored.

The OS allows you to create one or more partitions on your hard drive, in effect dividing it into several logical parts. Partitions let you install more than one operating system on your computer. You may also decide to split your hard drive because you want to store the OS and programs on one partition and your data files on another; this allows you to reinstall the OS when a problem occurs, without affecting the data partition.

The average time required for the read/write heads to move and find data is called seek time( or access time) and it is measured I milliseconds (ms); most hard drive have a seek time of 7 to 14 ms. Don’t confuse this with transfer rate – the average speed required to transmit data from the disk to the CPU, measured in megabytes per seconds.

How to protect your hard drive

Don’t hit or move the computer while the hard drive is spinning. Hard drives are very sensitive to vibration and shock, especially when they are operating; when the read/write head touches the rotating disk, it can scratch and damage the disk surface. This is known as head crash.

You shouldn’t turn your computer off and on quickly. Wait at least ten seconds to ensure that the drive has stopped spinning.

Check you hard drive regularly for logical and physical errors. To check and repair a drive, you can use a disk diagnosis utility like Windows ScanDisk

To minimize the risk of data lose or corruption, you should install an up-to-date virus scanner. You should also back up your hard drive regularly

UNIT11

Optical discs and drives

Optical discs can store data at much higher densities than magnetic disks. They are therefore ideal for multimedia applications where images, animation and sound occupy, a lot of disc space. Furthermore, optical discs are not affected by magnetic files, meaning that they are secure and stable, and can be transported through airport metal detector without damaging the dat. However, optical driver drives are slower than hard driver.

CDs and DVDsAt first sight, a DVD is similar to a CD. Both discs are 120mm in diameter and 1.2 mm thick. They also both use a laser beam to read data. However, they are very different in internal structure and data capacity. In a DVD, the tracks are very close together, thus allowing more track. The pits in which data is stored are also smaller, so there are more pits per track. As a result, a CD can hold 650- 700MB, whereas a basic DVD can hold 4.7GB.In addition, a DVD can be double-side and dual layer, with a capacity of 17GB

CDs come in three different format:  CD-ROMs (read-only memory) are read-only units, meaning you cannot change the data stored on them (for example, a dictionary or a game)

            CD-R (recordable) discs are write-once devices which let you duplicate music CDs and other data CDs

            CD-RW (rewritable) discs enable you to write onto them many times, just like a hard disk

DVDs also come in several formats:

            DVD-ROMs are used in DVD computer driver. They allow for data archiving as well as interactive content

            DVD-R or DVD+R can only be record on once

            DVD-RW or DVD+RW discs can erased and re-used many times. They are to back up data files and to record audio and video

The DVD drive used in computers is also called a DVD burner because it records information by burning via typically refer to a standalone unit which resembles a video cassette recorder. New DVD recorder can play all CD and DVD formats. There are also portable DVD player- handhelp devices which let you watch movies or TV, play game and listen to music, wherever you are. They come with a built-in DVD drive and widescreen LCD display. They usually support multi-format playback – that is, they can play many files formats, including DVD-video , DivX, CD audiodiscs, MP3 music and IPEG image.

HD-DVD and Blu-ray Discs

These two competing formats are expected to replace current DVD as standard for watching movies at home. On one side are Toshiba, Microsoft and the DVD Forum, who support the High Definition- DVD. Sony, Panasonic, Samsung, JVC and many movie studios are behind the Blu-ray format.

A Blu-ray discs has a capacity of 25GB (single layer), 50GB(dual layer) and 100Gb ( four layer). Unlike DVDs, which use a red laser to read and write data, Blu-ray use a blue- violet laser, hence its name. Blu-ray discs can record and play back high-definition television and digital audio, as well as computer data

UNIT12

Flash memory ia a type of non-volatile memory that can be electronically erased and reprogrammed, Its name was invented by Toshiba to express how much faster it could be erased – “in a flash”, which means very quickly

2.Unlike RAM, which ia volatetile, flash memory retains the information stored in the chip when the power is turned off. This makes it ideal for use indigital cameras laptops, network swithes,video games cards, mobile phones and portable multimedia player.In addition, it offers fast  read access times , with transfer rates of 12 MB per second. Unlike ROM chips, flash memory chips are rewritable, so you can update program via software.

3.Inside the chips, data ia stored in sereral floating gate transistors, called celd. Each cell traditionally stores one bit of data. New devises have a multi-level cell structure so they can store more that one bit parcel. The chips are constructed with either nor or nand gate. Nor chips function like acomputer’s main memory , while nand works like a hard driver. For example, in a camera, nor flash constains the camera’s internal software, while nand flash used ti store the images

Flash memory is used in seceral ways.

+many pc’s have their bios stored on a flash memory chip to it can be updated if necessary

+modem use flash memory because it allows the manufacture to support new protocol

4.usb flash driver are used to save and move mp3s and other data files between computer they are more easily transported than external hard driver because they use solid-state technology, meaning that they don’t have fragile moning parts that can break if dropped. However, usb flash srive rhave less storage capacity than hard driver.

 5.New U3 smart drivers allow users to store both applications and data. They have two driver partition and can carry applications that run n the host computer without requiring installtion.

Flash memory cards are used to store image on cameras, to back up data on PDAs, to transfer games in video consoles, to record voice and music on MP3 players. They are as small as a stamp, and capacity can range from 8MB to sergigabytes. The only limitation is that flash cards are often not interchangeable between devices. Some formats include: Comparctflash, secure digital, multimedia carci, own product called the memory stick, used in its digital still cameras, video camcoders ad the playstationportable. The photos stored in a via cable or wirelessly. Another option is to have a flash cad reader permanently eject the card from the camera and put it into the reader instead of having to plug the camera in.

The future of hard drivers may be hybrid hard drivers. Hybrid hard drivers combibe a magetic hard disk and flash memory into one device. This allows computers to boot, or start, more quichly, and also reduces power consumption.