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Bits and bytes. Lecturer: Andrew Waywood Unit: EDTS 100. Introduction. The information age is built on the digitizing of information. All information is reduced to binary form (represented as 1’s and 0’s and implemented in machines as switches that are either ON or OFF).
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Bits and bytes Lecturer: Andrew Waywood Unit: EDTS 100
Introduction • The information age is built on the digitizing of information. All information is reduced to binary form (represented as 1’s and 0’s and implemented in machines as switches that are either ON or OFF). • In this lecture we will build an overview of the processing of digitized information from the Integrated circuits of a modern computer through to the global digital network which is the Internet.
Topics of Discussion • The desktop computer • Connecting computers to form LANs (Local Area Networks) • Connecting computers and LAN’s to form WAN’s (Wide Area Networks) • TCP/IP The magic of computer to computer communication.
The desktop computer • The heart of the desktop computer is an integrated chip called the CPU (central processing unit) CPU
Random Access Memory Input/output addresses Network card The cpu is connected to the other components of the computer via a BUS. For a computer that is connected to a network one of the I/O address is linked to a network card. This card allows digital information to be passed between computers on a LAN. The BUS carries signals from the switches in the cpu to the internal storage of the computer which is its random access memory. Some memory address are special in that they connect to the outside world. They are like double sided pigeon holes. These are called I/O addresses. The RAM can be thought of as a group of pidgon holes each with a unique address that the cpu can send information to. CPU clock
If a device called a ROUTER is added to the backbone then the LAN can be joined to other Networks to form a Wide Area Network. To make the jump from one network to another it is usually necessary to go through a telecommunications carrier network like Telstra or Optus. Isdn pstn radio microwave nic router 10baseT ethernet hub nic nic The server side of the hub is known as the network backbone. Other hubs and other servers can be connected into this segment of the network to expand it and give it greater functionality. On modern LAN’s the network card is connected via copper wire to a hub. A hub or a stack of hubs can have between 4 and 100 computers connected through it. To allow all the computers to interoperate there needs to be a network operating system. The common network operating systems are Novell and WindowsNT. These operating systems are installed on a computer called the SERVER. Network card
Isdn pstn radio microwave USA R Denmark R router R R R UK The wide area network traffic is passed from router to router around the world. This network of routers is usually thought of as a cloud. You enter it from your computer and can make contact with any other computer that is connected to a router.
USA R R server R R R client The common language is known as TCP/IP and it works because every computer connected to the internet has a unique IP address. The client server architecture uses these IP addresses to send packets of information backwards and forwards between computers. Email, the WWW, FTP, Telnet, Internet relay chat, Internet phone, Internet radio, and many others, are all TCP/IP applications. The fact that your computer can talk with another computer on the other side of the world is achieved by having a standard protocol (language) which both computers understand, and what is called client server architecture.