Computer FundamentalsInstructor: Jun YanThursday (3, 4), N229, South Campus

Lecture 1: Computers, model of computation, and a guide for college study and life

陈婧 2050401571.

Welcome to the class.This lecture covers the following topics:

  1. Why should we learn this course?

1)12306:12306 is the phone number of Railway Customer Service Center of China.It uses computers to deal with the information from customers such as booking railway tickets or other service.[1]

2)GFW:GFW,the abbreviation of Great Firewall,is a system which uses computers to guarantee the security of Chinese Internet.It can reviewing and screening the information on the Internet automatically.[1]

3)Computer game:Nowadays,an increasing number of people choose computer games,which can not be accomplished without using computers to entertain themselves.

4)Shopping:Just by sitting in front of the computer and then clicking the mouse,people can buy almost everything on the Internet.It is computer which makes on line shopping a rising way to shopping.

The widely used computer raises the following question: how can we learn so many things about computer?

  1. This course is to teach us principles of computer

We are going to learn principles of computers. If we know the principles, then it would be much easier for us to learn any computer techniques quickly by ourselves.

In analog to Newton’s law. Teacher gives an example about Pluto and aircraft.Pluto used to be one of “the nine planets”.But a few years ago scientists kicked it off “the nine planets”with some evidence calculated by computers.They used computers to compute and found that Pluto didn’t meet the conditions of being the sun’s planets,which meant that it didn’t accord to the Newton’s law.

At the end of the semester, we shall know how each component of a computer work together to make computation possible.

  1. Content of this course[2]

Lecture includes:model of computation;data and logic;hardware;operating system;software and program;database;computer networks.

Experiment includes:hardware;software;website.

  1. von Neumann architecture[2]

Computer appears to us like a black box. The central question of this course is how to design this black box.

To see how to construct a computer in principle, let us first examine a simple calculation taught at elementary school, which serves as a motivating example.

3.14 * 7.2

First we calculate 4 times 2 and get 8.Then just like what we do just now,we calculate 1 times 2,3 times 2,4 times 7,1 times 7 and 3 times 7 orderly.Now we get two numbers:628 and 2198.Use what we have learned in primary school,we can easily get the answer:22.608.

Seeing from the calculation, we can extract three main ingredients of in our computation:

a)Multiplication table

b)Control

c)Blackboard

von Neumann architecture exactly captures the ingredients of computation mentioned above. The correspondence between von Neumann architecture and the calculation above is:

Multiplication/addition table-----Arithmetic logic unit

Blackboard/papers-----Memory

  1. Stored program and general-purpose computer

Now we can construct, in principle, a computer based on von Neumann architecture. We still have a problem: for each functionality, for example, phone, mp3, media player, game station, and so on, do we need to carry a specific computer for each of them?

Thanks to Turing, we have a single general-purpose computer to all the jobs! The underlying idea is to treat program as data. Write out in full detail.

Turing machine(the picture above)is a little machine which is as powerful as any computers in real world.Computer has its limitation.[2]

References

[1].baiki.baidu.com

[2].

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