Chapter One. Introduction to Computer System. Definition Objectives Types according to their size Internet

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Principles of Programming-I / 131101 Prepared by: Dr.

1 Principles of Programming-I / Prepared by: Dr. Bahjat Qazzaz Chapter One Introduction to Computer System Computer System Computer Networks Definition Objectives Types according to their size Internet Computer History

2 Computer Networks A computer network consists of two or more computers connected with each other directly or indirectly using communication medium. The communication medium can be wires such as twisted pairs (example, the telephone lines) and fiber optics, or it can be wireless such as microwave, Bluetooth, infrared,...etc. The computer networks are mainly used for the following reasons: 1. Resources sharing: is to share hardware (such as printers) and software (programs, and databases). 2. Saving money: sharing resources lead to saving money. Also, it is becoming normal to make correspondences and exchange documents over the network without traveling. 3. Reliability: since there many computers connected to the network, it is possible to make a backup of your important files on different computers, and if your computer caches then, you can still have a copy of your data on other device. 4. Communication facility: computer networks let the people to communicate between each other and it became a way of amusement. The network can be classified according to their sizes. The famous type is the LAN (Local Area Network). In LANs, a set of computers inside a computer, company, institution, or university campus is connected to each other. So, LANs cover a building or a campus. Another type is MAN (Metropolitan Area Network) which covers a whole city. A third type is WAN (Wide Area Network) which can be spanned over the whole country or continent. The question is: where does the Internet is located among these types. In fact, after each university, institution, office, department has its own LAN, these organizations had the need to connect to each other. So, the Internet is a collection of LANs (and may be MANs and WANs) interconnected with each other. Each computer on the Internet has and address called IP address by which the computer is identified so that messages can reach their destination based on the IP address. The most famous paradigm work over the internet is the client/server model. The server has a service that it can offer whenever it is requested, and the client request the service.

3 Example, when you connect to a web page, or when you connect to Azzajel of An-najah University Registration Program. Computer History and Generations During World War II, the US military needed a computer to help them for calculating the trajectory tables for their weapons so, in 1943 they started working on developing a computer called ENIAC (Electronic Numerical Integrator and Computer). The work has finished in 1946, after the war has finished and thus, it was not used in the war. Instead, ENIAC was used to perform complex calculations for making the hydrogen bomb. In 1955, ENIAC was disassembled. It was weighing 30 tons, occupying square feet of space, and containing more than vacuum tubes. It was consuming a lot of power and producing a lot of heating. In addition, it was difficult to program with it. In 1946, the mathematician Von Nuemann and his colleagues proposed a new design consisting of Main Memory, ALU, CU, and I/O equipments operated by the CU. The idea was to store the program in the memory to be executed thereafter. The new computer completed in 1952 and its basic architecture is still used until these days as a prototype for all subsequent general-purpose computers. The 1950s witnessed the birth of the computer industry. The first and second versions of UNIVAC (Universal Automatic Computer) were the first successful commercial computers. In late 1950s, computers industry used the new technology of transistors. Transistors made the computer smaller in size, cheaper, and produced less heat. As a result, more complex ALUs an CUs have been introduced, and high-level languages were used. In late 1950s and early 1960s, the ICs (Integrated Circuits) were invented. With the ICs, many discrete components (transistors, capacitors, resistors) were collected in a thin silicon chip (IC) where each IC has specific job with input and output terminals (pins). The history of computer developments have been divided into generations called Computer generations. Also, many companies were leading the computer industry such as IBM and DEC, and many scientists were leading the researches of the computer development such Eckert, Mauchly, Von Nueman and others.

4 In this course, you are required to write a small report (research) about the computer generations including the key factor of each generation, the fabrication companies, major computer names, scientists and institutions participated in the computer development. Or choose on of the following assignment. Classifying Computers According to their Size 1. Main frame: It is a big central computer to which many terminals (called peripherals) are connected. Each user has an account and password and connects to the computer by logging in to the computer. This computer is very fast yet (but) it is very expensive. 2. Miniframe: It is a smaller version of the mainframe and it works in the same manner. It is fast but less expensive than the mainframe. 3. Personal Computer (PC): the PCs are becoming available in all the universities, institutions, and they are entering almost every home. They are easy to move from one place to another and occupy less space than the previous ones. In fact, the dramatic development in the PC technology (speed, storage system, price, size) made them famous. 4. Laptop, Palm, handheld: these devices are becoming as powerful as PC. People need such devices when they travel or in the field work. 5. Servers: The computer servers have replaced the mainframe and mini-frame computers and are widely used in networking and Internet. The today servers are more powerful than the old age mainframe, less in size, faster, have huge storage and less expensive. 6. Super computers: these are huge computers used usually for research purposes especially simulations. Cray super computer is an example of such computers. 7. Parallel computer: it is a single machine which has many processors connected to each other on the same board. The task to be processed can be distributed among these processors to achieve the required job in a less time. Research Papers (Homework) 1. History of Computers, Computer Generations 2. Computer types according to their sizes

5 3. Input and Output devices 4. Programming languages development 5. Printers

ENIAC - background. ENIAC - details. Structure of von Nuemann machine. von Neumann/Turing Computer Architecture

ENIAC - background. ENIAC - details. Structure of von Nuemann machine. von Neumann/Turing Computer Architecture 168 420 Computer Architecture Chapter 2 Computer Evolution and Performance ENIAC - background Electronic Numerical Integrator And Computer Eckert and Mauchly University of Pennsylvania Trajectory tables