Chapter 1 Introduction to Computers Maran Illustrated Computers CIS 102 1

Hardware 2

Software 3

Getting Help 4

How Computers Work in General 5

Input devices 6

Process (CPU) 7

Output 8

Storage device 9

Data representation in Bytes 10

Computer Memory Memory is comprised of a large collection of bi-state (off/on) electrical devices called bits (binary digits) A single bit can assume the value 0 or 1. A single bit is not sufficient to represent all data ; therefore, it is necessary to use a sequence of bits.

Computer Memory How many bits are needed in a bit pattern to represent a symbol in a language? A bit pattern of size 1 can represent two different pieces of information. For example, to represent pass / fail we could use 0 - Fail 1 - Pass

Binary system The binary system is based on 2. There are only two digits: 0 and 1 We convert a number from binary to decimal by multiplying each binary digit by its corresponding power of 2. i.e. Multiply the bit at position n (n = 0, 1, 2, …) by

Figure 3-1 Decimal system

Figure 3-2 Binary system

Binary to Decimal Conversion Binary number

Figure 3-3 Binary to decimal conversion

1.Convert the binary number to decimal. 2.Convert the binary number to decimal. Exercises

Example 1 Convert the binary number to decimal. Solution Write out the bits and their weights. Multiply the bit by its corresponding weight and record the result. At t Write out the bits and their weights. Multiply the bit by its corresponding weight and record the result. At the end, add the results to get the decimal number. Binary Weights

Exercises 1.Convert the decimal number 35 to binary. 2.Convert the decimal number 327 to binary.

Base 8 (Octal ) Bit Pattern Bit Pattern Octal Digit Octal Digit Valid digits: 0, 1, 2, 3, 4, 5, 6, 7

Base 16 - Hexadecimal Bit Pattern Bit Pattern Hex Digit Hex Digit Bit Pattern Bit Pattern Hex Digit Hex Digit A B C D E F Valid digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F

Converting from base 2 to hexadecimal To convert from base 2 to hexadecimal 1. Organize the stream of binary digits into groups of four. 2. Find the hexadecimal value for each group of 4 bits E 1 A

Converting from hexadecimal to base 2 To convert from hexadecimal (base 16) to base 2 Convert each digit to its 4-bit equivalent. 9 2 E 1 A

Binary to hexadecimal and hexadecimal to binary transformation

1.Show the hexadecimal equivalent of the bit pattern Show the hexadecimal equivalent of the bit pattern What is the bit pattern for 2675 base 16? 4.What is the bit pattern for B51E base 16? Exercises

Review number systems Review base 10 Review base 2 (binary) Review base 16 (hexadecimal) Convert from decimal to binary Convert from binary to decimal Convert between binary and Hexadecimal See notes for links covering these topics 27

Types of computers 28

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Surge Protector 33

UPS 34

Monitor Port 35

Sound Ports 36

Modem port 37

Ethernet (Network) Port 38

USB port 39

Firewire port 40

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Daisy chaining 42

Plug and Play 43

Adding ports to your computer 44

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Expansion slots 46

Connect devices 47

High-End video 48

Firewire or USB

High-End Sound 50

Network Interface Card (NIC) 51

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