计算机概论复习：英文和截图

为考试做的复习笔记。

Chap0 Introduction:CS,short for Computer Science

What is computer science?

The science about computing and its applications.

Algorithm

is a set of steps that define how a task is performed.

began as a subject in mathematics,the goal was to find a single set of directions that described how all problems of a particular type could be solved.

capability of machine.

software=program+algorithm+data;

system=software+hardware.

计算机出现的历程：相关历史：

1946-1954 vacuum tubes 真空管；
1954-1964 transistor 晶体管；
1964-1971 intergrated circuits 集成电路IC；
1971~ very large scale IC VLSI；

Chap1 Data Storage

bits and their storage

Bits: Binary Digit(0 or 1) 二进制位；

Specific operation

XOR：亦或，不同为真。即0 和 1 为 1；

hexadecimal

exercise：

四位一个。

From Decimal to Binary

Binary addition

ps：二进制中没有减法，只有加法，故要做减法时，只能把减数转为负数再做和。

关于取负数

关于一个数的负数：取反再加1；

此数的第一位若是0，则为正数；若1，则为负数。

如：

关于位的范围

三位，则-4~3，即-2^(3-1) -2^(3-1)-1
记住：负数的绝对值比正数多1；

Others

Chap2 Data Manipulation

computer architecture

machine language

第一个3是操作码，后面的是操作数。


PC是指针指向的地址，两位的。
IR是即将完成的指令，四位的。

要重点复习附录C。

Chap3 Operating Sysrems

Software Classification

Chap4 Networking and the Internet

Internet applications

World Wide Web

Chap5 Algorithms

definition

表示算法的方式

natural language;
flowcharts;
pseudocode;
programming language;

Two Algorithm

Sequential Search Algorithm:
顺序查找法；

Binary Search Algorithm：
二分查找法；

Chap6 Programming languages

Generations of programming languages

1 machine language
2 assembly language
3 high level programming language
4 Non-Procedural Language

Complier & interpreter

compiler 效率高

Historical perspective