Powered by Blogger.

About Me

Believe in Miracles

Followers

RSS

You can replace this text by going to "Layout" and then "Page Elements" section. Edit " About "

Chapter 9

07:50 |

Modulation



Modulation is the process where a Radio Frequency or Light Wave's amplitude, frequency, or phase is changed in order to transmit intelligence. The characteristics of the carrier wave are instantaneously varied by another "modulating" waveform.




Demodulation


The process of separating the original information or signal from the modulated carrier. In the case of amplitude or frequency modulation it involves a device, called a demodulator or detector, which produces a signal corresponding to the instantaneous changes in amplitude or frequency, respectively. This signal corresponds to the original modulating signal. In radio transmission this process is a major function of a receiver, in order to retrieve the desired signal.




Bandwidth


In computer networking and computer science, bandwidth, network bandwidth, data bandwidth, or digital bandwidth is a bit rate measure of available or consumed data communication resources expressed in bits/second or multiples of it. Bandwidth refers to analog signal bandwidth measured in hertz. Some computer networking authors prefer less ambiguous terms such as bit rate, channel capacity and throughput rather than bandwidth in bit/s, to avoid this confusion.




TCP/IP


TCP/IP the suite of communications protocols used to connect hosts on the Internet. TCP/IP uses several protocols, the two main ones being TCP and IP. The transmission control protocol assembles the file into smaller packets to be transmitted over the internet. Whereas the internet protocol handles the address part of each packet so it reaches the correct destination.




Node


In a network, a node is a connection point, either a redistribution point or an end point for data transmissions. In general, a node has programmed or engineered capability to recognize and process or forward transmissions to other nodes.




Client


A client is an application or system that accesses a remote service on another computer system, known as a server, by way of a network. The term was first applied to devices that were not capable of running their own stand-alone programs, but could interact with remote computers via a network. In personal computers and computer workstations, the difference between client and server operating system is often just a matter of marketing.




Server


In information technology, a server is a computer program that provides services to other computer programs (and their users) in the same or other computers. In the client/server programming model, a server is a program that awaits and fulfills requests from client programs in the same or other computers. A given application in a computer may function as a client with requests for services from other programs and also as a server of requests from other programs.




Network Operating Systems



A network operating system (NOS) is a computer operating system that is designed primarily to support workstation, personal computer, and, in some instances, older terminal that are connected on a local area network (LAN). A network operating system provides printer sharing, common file system and database sharing, application sharing, and the ability to manage a network name directory, security, and other housekeeping aspects of a network.




Network Administrator


Network administrators are the people who are responsible for maintaining the hardware and software that run these networks that keep you connected to the world. Network administrator will be in charge of maintaining these networks and repairing and troubleshooting problems with the network.

  • Digg
  • Del.icio.us
  • StumbleUpon
  • Reddit
  • RSS
Read User's Comments(0)
Posted by wei ling

Secondary storage

05:26 |

Dick caching



Disk caching is a mechanism to improve the time needed to read/write onto a hard disk. It is usually part of the hard disk. It holds data that has been most recently used in order to speed up the access of that data. When a program needs to access new data, the operating system checks if the data is in the cache before reading it from the disk. Data from the RAM can access much faster than from a disk, disk caching helps increase performance.




File Compression


File compression is commonly used when sending a file from one computer to another over a connection that has limited bandwidth. The compression basically makes the file smaller and, therefore, the sending of the file is faster. Of course, when compressing a file and sending it to another computer that computer has to have a program that will decompress the file so it can be returned to "normal" and used.




File Decompression



File decompression is when you return the file to its original size by extracting it or unarchiving it. Sending and receiving compressed files across the Internet is a common activity.




Internet Hard Drive


Internet hard drives enable the users to backup their files on the Internet through many backup servies available.Backing up files on the Internet may take a long time, as it depends on the speed of the internet. Likewise, uploading your file back on the computer may also take a long time. However, what internet hard drive offers is the freedom to retrieve any document you need from anywhere in the world.




Optical Diskdrive

The optical disc drive (ODD) is a disk drive which uses low-powered laser light or electromagnetic waves near the light spectrum to read or write data to or from optical discks. Optical disc drivs are circular, flat, glass or plast disk in which data can be stored in the form of light and dark pits.  Often, ODD are called burners or writers. CD's, DVD's and blu-ray discs are the common types of optical media that can be read and written on by such drives.




Solid State Storage

A solid-state storage is a type of nonvolatile, removable data storage device which uses solid-state memory to keep persistent data. It is distinguished from traditional hard disk drives, which are electromechanical devices containing spinning disks and movable read/write heads since solid-state storage does not contains any mechanical parts.

  • Digg
  • Del.icio.us
  • StumbleUpon
  • Reddit
  • RSS
Read User's Comments(0)
Posted by wei ling

Input and output

03:44 |

Ergonomic Keyboard



An ergonomic keyboard is a computer keyboard designed with ergonomic considerations to minimize muscle strain and a host of related problems. Typically such keyboards are constructed in a V shape, to allow right and left hands to type at a slight angle more natural to the human form.




Ink Jet Printer


An inkjet printer is a type of computer printer that creates a digital image by propelling droplets of ink onto paper. Inkjet printers are the most commonly used type of printer and range from small inexpensive consumer models to very large professional machines, that can cost up to thousands of dollars. The emerging ink jet material deposition market also uses inkjet technologies, typically printheads using piezoelectric crystals, to deposit materials directly on substrates.




Laser Printer


A type of printer that utilizes a laser beam to produce an image on a drum. The light of the laser alters the electrical charge on the drum wherever it hits. The drum is then rolled through a reservoir of toner, which is picked up by the charged portions of the drum. Finally, the toner is transferred to the paper through a combination of heat and pressure. This is also the way copy machines work. Laser printers produce very high-quality print and are capable of printing an almost unlimited variety of fonts.




Magnetic Ink Character


Magnetic ink characters (MIC) are numbers, letters, or symbols that are usually used in conjunction with magnetic ink recognition technology. This technology is primarily used by the banking industry to read and sort checks using a process called Magnetic Ink Character Recognition or MICR. MICs are printed at the bottom of a check in the MICR line and are usually 3 or 4 sets of numbers and symbols.




Optical Character Recognition


Optical character recognition, usually abbreviated to OCR, is the mechanical or electronic translation of scanned images of handwritten, typewritten or printed text into machine-encoded text. It is widely used to convert books and documents into electronic files, to computerize a record-keeping system in an office, or to publish the text on a website. OCR systems require calibration to read a specific font; early versions needed to be programmed with images of each character, and worked on one font at a time.




Optical Mark Recognition


optical mark recognition, the technology of electronically extracting intended data from marked fields, such as checkboxes and fill-infields, on printed forms. OMR technology scans a printed form and reads predefined positions and records where marks are made on the form. This technology is useful for applications in which large numbers of hand-filled forms need to be processed quickly and with great accuracy, such as surveys, reply cards, questionnaires and ballots. A common OMR application is the use of "bubble sheets" for multiple-choice tests used by schools.

  • Digg
  • Del.icio.us
  • StumbleUpon
  • Reddit
  • RSS
Read User's Comments(0)
Posted by wei ling
Subscribe to: Posts (Atom)