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Information Technology Computers became an inseparable and important part of our everyday life. We use advantages of computer technologies in every sphere of our life. It is hard to believe that not so long ago such device as notebook was merely a science fiction fantasy. It is more important for us to use computer devices properly. We also need to learn what method of output and input would be best for different documents. Input devices help us to enter information into the computer.
There are different input devices: mouse, keyboard, scanner, light pen, graphics tablet, joystick, trackball, voice recognition device. Lets take a closer look on the scanners. Estera's states Scanners convert text or picture into electronic codes that can be manipulated by the computer. (Infotech, 1999). If we want to scan some long document it is better to use sheet-fed scanner. Jeff Tyson pointed that Sheet-fed scanners are similar to flatbed scanners except the document is moved and the scan head is immobile.
A sheet-fed scanner looks a lot like a small portable printer. (How Scanners Work). You can just put the document into the scanner and it will do all work for you. On other hand, printed questionnaires better scan with the help of common flatbed scanners. According to Jeff Tyson: Flatbed scanners, also called desktop scanners, are the most versatile and commonly used scanners.
In fact, this article will focus on the technology as it relates to flatbed scanners (How Scanners Work). Questionnaires have no images, they are printed on the common paper, as result it is better to use flatbed scanners. The best way to scan the telephone survey, in my own humble opinion, is to use drum scanner. Telephone surveys always use images, this and other distinctive feature of telephone surveys are the reasons for using drum scanner.
Drum scanners are used by the publishing industry to capture incredibly detailed images. They use a technology called a photo multiplier tube (PMT). In PMT, the document to be scanned is mounted on a glass cylinder. At the center of the cylinder is a sensor that splits light bounced from the document into three beams. Each beam is sent through a color filter into a photo multiplier tube where the light is changed into an electrical signal. (How Scanners Work). If we want to scanner something small, with uncommon size and shape we must use handheld scanners.
Jeff Tyson pointed out Handheld scanners use the same basic technology as a flatbed scanner, but rely on the user to move them instead of a motorized belt. This type of scanner typically does not provide good image quality. However, it can be useful for quickly capturing text. What else can we use for scanning bank checks or retail tags? They contain only text and handheld scanners are the best choice. Output devices help us to see the results of the processed data.
Printers and monitors are the most widely used output devices. We will talk about printers. For different purposes we use different kinds of printers. Printers vary in compatibility, noise, quality, etc. For example for hand held computer I would rather choose printer with infrared port or with common USB port. It would give easier access if port would be situated on the front panel of the printer.
No plotters (construction plans, technical illustrations, etc. ) and photo setters (photographs, images with high resolution). Hand held computers are not specified for such information. Simple ink-jet or laser print will suffice enough. As for the color photographs photo setter is the only choice. Estera's pointed that Photo setters print only on photographic paper or microfilm. It can produce output with a resolution of over 2, 000 per inch. (Infotech, 1999) I think, that for resume or memorandum it is better to use simple ink-jet printers.
Resume or memorandum do not contain images, high quality and speed is not necessary for them. On other hand if we need to print statistical report or company annual reports it is better to use color laser printer. Laser printers produce output at great speed and very great resolution 600 / 1, 200 dpi. They have wide range of scalable fonts, they can emulate different language systems and produce high quality graphics. (Estera, Infotech, 1999) Colorful diagrams, tables and graphs are widely used in statistical reports and company annual reports. That is why, I think, it is better to use color laser printer for them. It is needless to day that we have to store information whether it is used with the computers or other technical devices.
According to Marshall Brain Magnetic recording is a backbone technology of the electronic age. It is a fundamental way for permanently storing information. (How Tape Recorders Work) We use magnetic tape when we want to store audio or video information. It is not very compact and devices for reading and writing the tape are rather cumbrous. The main advantage of the tape is its price magnetic tape is rather cheap. As for the computer storage devices they can me divided into the internal (hard disks, RAM) and external (floppy disks, CD disks). Hard disks (so as floppy disks and CD disks) are permanent storage devices.
You can keep information on them as long as you want. According to the fact that capacity of hard disks are 250 Mb and more the amount of information you can store is quite impressive. It can be audio and video data, images and texts, etc. Everything you transfer into digital form you can keep on the hard disk. On the other hand RAM (random access memory) is temporary, i. e.
that its information is lost when the computer is turned off. The microprocessor used RAM when user runs an application. The microprocessor looks for it on disks and then transfers the copy of the application into the RAM area. The information on a hard disk is stored in extremely small magnetic domains compared to a cassette tapes. The size of these domains is made possible by the precision of the platter and the speed of the medium. Floppy disks and CD disks can store the same kind of information as the hard disks but their capacity differs greatly.
Floppy disks use the same technology as hard disks but can contain no more than 2, 56 Mb. They are very compact and can be used for storing small amount of data. Estera pointed that CD disks (optical disks) can store information at much higher densities than magnetic disks. They are ideal for multimedia applications where images, sound and animation occupy a lot of disk space (Infotech, 1999) Their capacity is 600 - 700 Mb. Data can be transferred into the computer and to the applications in various speeds. Lets see on what factors speed depends on.
The speed of computer is partly determined by the speed of microprocessor. A clock provides pulses at fixed intervals to measure and synchronize circuits and unites. The clock speed is measured in MHz (megahertz) and refers to the frequency at which pulses are emitted (Estera, Infotech, 1999). The RAM memory also has different capacity, from 128 Mb to 512 Mb on average. The largest amount of RAM memory provides higher speed. They ways of retrieving data from floppies and hard disks are similar.
The surfaces of disks are divided into concentric circles or tracks, which are then divided into sectors. For each track and sector magnetic areas are created after initializing, along with a catalogue which will record the specific location of files. When you save or retrieve data, the operating system moves the read / write heads of the disks drive towards sectors and read / write an entry for the directory. For the hard disks such procedures takes form 8 ms to 20 ms. Floppies are much slower. Retrieving data from the CD disks takes more time that from hard disks but less then from floppies.
Bibliography Santiago Re macha Estera's, Cambridge University Press (1999), Infotech. Retrieved March 16, 2005. Jeff Tyson, How Scanners Work. Retrieved March 16, 2005 from web Marshall Brain, How Tape Recorders Work. Work.
Retrieved March 16, 2005 from web Printers and feature. Retrieved March 16, 2005 from web Prices and Features. Retrieved March 16, 2005 from web
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