Communication and Network

Modulation
Demodulation
Bandwidth
TCP/IP
Node
Client
Server
Network Operating Systems
Network Administrator




Modulation

  • also known as continuous wave modulation
  • the addition of information (or the signal) to an electronic or optical signal carrier
  • can be applied to direct current (mainly by turning it on and off), to alternating current, and to optical signals
  • examples of modulation methods are Amplitude modulation (AM), Frequency modulation (FM), Phase modulation (PM)
  • to encode both digital and analog information in a binary way
Demodulation
  • the process of recovering the audio-frequency signal from the modulated wave is known as demodulation or detection
  • used in connection with radio receivers
  • Modulation is the addition of information (or the signal) to an electronic or optical signal carrier
  • can be applied to direct current (mainly by turning it on and off), to alternating current, and to optical signals
  • used in amateur radio, modern computers
  • examples of modulation methods are Amplitude modulation (AM), Frequency modulation (FM), Phase modulation (PM)
Bandwidth
  • also known as network bandwith, data bandwith, or digital andwith
  • is a bit rate or net bit rate(also known as peak bit rate, information rate or physical layer useful bit rate)
  • measure of a logical or physical communication path in a digital communication system
  • measure the maximum throughput of a computer network

TCP/IP
  • also known as Transmission Control Protocol/Internet Protocol
  • is a description framework for computer network protocol
  • is a set of general design guidelines and implementations of specific networking protocols to enable computers to communicate over a network 
  • used to connect hosts on the Internet 
Node
  • is a connection point
  • has programmed or engineered capability to recognize and process or forward transmissions to other nodes
  • can be a computer or some other device, such as a printer
Client
  • is an appication or system that accesses a remote service on another computer system 
  • not capable of running their own stand-alone programs, but could interact with remote computers via a network
  • is the requesting program or user in a client or server relationship

Server
  • a computer program running to serve the needs or requests of other programs which may or may not be running on the same computer.
  • a physical computer dedicated to running one or more such services, to serve the needs of programs running on other computers on the same network.
  • a software/hardware system (i.e. a software service running on a dedicated computer) such as a database server, file server, mail server or print server 

Network Operating Systems
  • also known as NOS or Dialoguer
  • runs on a server and enables the server to manage data, users, groups, security, applications, and other networking functions
  • allow shared file and printer access among multiple computers in a network
  • Secure access to a network
  • Back up data and make sure it's always available
  • Monitor the status and functionality of network elements
Network Administrator

  • also known as network admin
  • is the person responsible for the maintenance of computer ardware and software that comprises a computer network
  • their jobs include deploying, configuring, maintaining and developing active network equipment
  • support personnel that only work on break/fix issues that could not be resolved
  • manages a local area communications network (LAN) or wide area network (WAN) for an organization

Secondary Storage

  • Disk Caching
  • Gile Compression
  • File Decompression
  • Internet Hard Drive
  • Optical Disc Drive
  • Solid-State Storage
Disk Caching
  • is a mechanism for improving the time it takes to read from or write to a hard disk 
  • included as part of the hard disk
  • can also be a specified portion of random access memory(RAM)
  • holds data that has recently been read and, in some cases, adjacent data areas that are likely to be accessed next



File Compression
  • also know as Data Compression
  • to encode data before sending it to another place
  • commonly used when sending a file from one computer to another over a connection that has limited bandwidth
  • makes the file smaller and, therefore, the sending of the file is faster


File Decompression
  • reverse of  file compression-decoding of compressed data to restore the unique data


Internet Hard Drive
  • to access user's computer files such as pictures, documents, music, videos, etc. from any computer, as long as that computer has access to the Internet
  • unlike local hard drive, an internet hard drive provides unlimited disk space
  • lower risk to loose documents

Optical Disc Drive
  • also known as ODD
  • uses laser light or electromagnetic waves to read the data from a disc
  • used in computers to read software and consumer media distributed in disc form, and to record discs for archival and data exchange

Solid-State Storage
  • also known as SSD
  • is a data storage device that uses solid-state memory to store data providing access in the same manner of a traditional hard disk drive
  • it contains no mechanical parts, everything is done electronically
  • data transfer at a much higher speed

Input and Output

  • Ergonomic Keyboard
  • Ink-Jet Printer
  • Laser Printer
  • Magnetic-Ink Printer
  • Optical-Character Recognition
  • Optical-Mark Recognition

Ergonomic Keyboard 


  • computer keyboard that separates the keys into two halves shaped like a wide "V"
  • some have a fixed layout, while others are movable
  • puts less stress on the hands and wrist and winds up being comfortable platform for typing, for most people.
  • designed to to relieve sometimes painful conditions, minimize muscle strain and a host of related problems




Ink-Jet Printer


  • forms an image by using electromagnetic fields to guide electrically charged ink streams onto the page.
  • propels droplets of ink directly onto the medium
  • uses cyan, magenta, yellow and black
Laser Printer
  • produces high quality text and graphics
  • uses a non-impact
  • utilizes a laser beam to produce an image on a drum
  • 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
  • the toner is transferred to the paper through a combination of heat and pressure
Magnetic-Ink Character Recognition


  • also known as MIRC
  • character recognition system that uses special ink and characters
  • used by banks to read unusual numbers and characters found on the bottom of checks
  • provides a secure, high-speed method of scanning and processing information



Optical-Character Recognition


  • also known as OCR
  • recognition of printed or written text characters by a light source and convert into ASCII code
  • analyzes the light and dark areas of the bitmap in order to identify each alphabetic letter and numeric digit
  • used to read retail price tag in departmental stores, in libraries to digitize and preserve their holdings and ect


Optical-Mark Recognition


  • also known as OMR
  • scans and senses the presence or absence of mark or character 
  • the use of "bubble sheets" for multiple-choice tests used by schools

High Definition Multimedia Interface port

High-Definition Multimedia Interface is also known as HDMI.

HDMI is :
  • compact audio/video interface for transmitting uncompressed digital data
  • connects digital audio/video sources for examples HD DVD player, PlayStation 3 to compatible digital audio devices like video projector and digital TV

Ethernet port

Ethernet port is a family of frame-based computer-networking technologies which connects the computer to the internet modem for local are networks (LAN).

Firewire port

Firewire port also known as High Performance Serial Bus (HPSB).

Firewire is :
  • allows connetion between a computer to many different types of peripheral devices
  • a very high-speed rate of data transfer that will accommodate multimedia applications for example digital camcorder

Parallel port

Parallel port is also known as :

  • printer port 
  • Centronics port



A Parallel port is :

  • socket on a computer used to connect various peripherals
  • to send or receive a huge amount of data in a short distance
  • allows eight data bits transferring simultaneously

Serial port

Serial port is :

  • A socket on a computer used to connect a modem, or other device especially in data acquisition terminal
  • runs at a very slow speeds
  • on the back of a PC is a male 9-pin connector
  • good for long distance

Universal Serial Bus port

Universal Serial Bus port also known as USB.

The USB is :

  • the most common type of computer port used in today's computers
  • used to connect devices like keyboards, mice, game controllers, printers, scanners, digital cameras ect
  • faster than older ports, such as serial and parallel ports

Plug and Play

Plug and Play is:

  • allows to add new components or devices to a system automatically 
  • for examples: headphone, microphone, mouse ect
  • recognizes the attached peripheral devices then adjust the appropriate internal settings when starting the computer

Network Interface Card

Network Interface Card also known as NIC.

Netwok Interface Card is :
  • a computer circuit board
  • a card that is installed in a computer to make connection between it and the network cable
  • provide a dedicated, full-time connection to a network

Sound Card

Also called :
  • Sound Board
  • Audio Adaptor

Sound Card is :
  • a plug-in card that records and plays back sound
  • provide an input port for a microphone or other sound source
  • output ports to speakers and amplifiers

Graphic Card

Also known as :

  • Video Card
  • Video Adapter
  • Graphic Adapter



Graphic Card is :

  • the plug-in card in a desktop computer
  • creates the electronic signals required by the monitor
  • an expansion card that allows the computer to send graphical information to a video display device

Flash Memory

Flash Memory is :


  • a non-volatile computer storage chip that can be electrically erased and reprogrammed.
  • primarily used in memory cards, USB flash drives, MP3 players and solid-state drives.
  • used for general storage and transfer of data between computers and other digital products.

ROM

ROM stands for Read-Only Memory.


ROM is :

  • nonvolatile
  • computer memory on which data has been prerecorded
  • data cannot be removed and can only be read
  • retain its contents even when the computer is turned off
  • used extensively in calculators and peripheral devices such as laser printer

Cache

Cache is :

  • to store data locally in order to speed up subsequent retrievals
  • Reserved areas of memory in every computer that are used to speed up instruction execution, data retrieval and data updating.
  • serve as staging areas, and their contents are constantly changing.
  • take advantage that same data item is often reused many times.
  • holds copies of recently accessed data such as a web page and pictures on web pages

RAM

RAM stands for Random Access Memory.


RAM is :

  • small, both in physical size and in the amount of data it can hold.
  • any storage location can be accessed directly
  • faster to read from and write to than the other kinds of storage in a computer, the hard disk, floppy disk, and CD-ROM.
  • data in RAM stays there only as long as your computer is running