Part 1, Computing FundamentalsChapter 1, Computer Basics

Lesson 1-1, What is a computer

Robert Crawford, MBAWest Middle School

Describe the four operations of a computer Contrast analog and digital computers Explain why data and instructions for

computers are coded as 0’s and 1’s

UNIT O BJECTIVES

Bit Byte Computer Input Output Processing Storage

KEY TERMS

What is a computer?◦ try to think in general terms:

don’t just form a answer that describes a computer as it exists today

Try too think of an answer that would work both into the past (think in terms of about 500

years). The first use of the word “computer” was

recorded in 1613 in a book called “The yong mans gleanings”

Into the future

Computer basics

What is a computer?◦Originally It referred to a person who carried out calculations, or computations, and the word continued with the same meaning until the middle of the 20th century.

◦From the end of the 19th century the word began to take on its more familiar meaning, a machine that carries out computations.

Computer basics

What is a computer?◦This takes us to where we are today with this definition. . .

A machine that changes information for one form into another.

Computer basics

What is a computer?◦A machine that changes information for one form into another.

◦It does this by performing four basic operations.

Computer basics

What is a computer?◦A machine that changes information for one form into another.

◦It does this by performing four basic operations. Input Processing Output Storage

Computer basics

Computer basics

AnalogDigital

◦ Measures data in a scale with many values Mercury

Thermometer Gas gauge on

a car

Works with data that has fixed values◦ Typically 1 and 0◦ The computers you are

using right now are digital computers.

Computer basics

Analog

Digital

The raw (unaltered) information that is entered into the computer.◦ Simple

Letters Numbers

◦ Complex Photographs Videos Music

◦ How do we get information into the computer?

Input

The raw (unaltered) information that is entered into the computer.◦ Simple

Letters Numbers

◦ Complex Photographs Videos Music

◦ We input information into the computer using a variety of devices.

Input

Information is stored, and processed, in the computer in a very basic format.◦ 1’s and 0’s

Input

Information is stored, and processed, in the computer in a very basic format.◦ 1’s and 0’s◦ A single unit of information is a Bit

Short for “Binary Digit”

Input

Information is stored, and processed, in the computer in a very basic format.◦ 1’s and 0’s◦ A single unit of information is a Bit

Short for “Binary Digit”◦ These Bits are grouped together in “words” called

“Bites” For example (i.e.)

A = 01000001 1 = 00110001

This is the only way the computer sees information.

Input

Processing is the second step in the information processing cycle.

Processing

Processing is the second step in the information processing cycle.◦ Remember, the four operations of computers

are: Input Processing Output Storage

Processing

Processing is the second step in the information processing cycle.◦ In this step the computer manipulates (does

something with) the data.

Processing

Processing is the second step in the information processing cycle.◦ In this step the computer manipulates (does

something with) the data. This stage is largely dependent on two

things:◦ Coded Instructions◦ Speed of processing

Processing

Processing is the second step in the information processing cycle.◦ In this step the computer manipulates (does

something with) the data. This stage is largely dependent on two

things:◦ Coded Instructions

These are the instructions given to the computer, the program. High Level Code (C++, Pascal, Python) Low Level Code (machine code, assembly language)

◦ Speed of processing

Processing

Motorola MC6800 Assembly listing, showing original assembly language and the assembled form

Processing is the second step in the information processing cycle.◦ In this step the computer manipulates (does

something with) the data. This stage is largely dependent on two

things:◦ Coded Instructions

These are the instructions given to the computer, the program. While this class is not a programming class, there will be

more about these in future units

◦ Speed of processing

Processing

Processing is the second step in the information processing cycle.◦ In this step the computer manipulates (does

something with) the data. This stage is largely dependent on two

things:◦ Coded Instructions◦ Speed of processing

Speed is measured in units of cycles per second, which is called a Hertz (Hz). Computer boards and CPUs run at rates of millions and billions of Hertz, megahertz (MHz) and gigahertz (GHz). A good speed for a PC microprocessor in 2004 was 4

GHz.

Processing

The third step of the information processing cycle is output.◦ After the computer adds two numbers the

computer then presents the result; this is output.◦ Output can take many forms.

Output

The third step of the information processing cycle is output.◦ After the computer adds two numbers the

computer then presents the result; this is output.◦ Output can take many forms.

Image Monitor

Sound Speaker

Printed text Printer

Tactile feedback PS4 vibrating controller

Output

The four the operation is storage.

Storage

The four the operation is storage.◦ What would happen without computer storage?

Storage

The four the operation is storage.◦ Without computer storage all of the work you do

on the computer would be lost.◦ By storing the data you can access it and use that

data at a late date. We will talk more about storage in the next, and

other future, units.

Storage

Things to remember

Work with the person next to you and try to think of things that you should expect to see on an examination.

Things to remember

Use a sequence chart to place the four operations of computers in their correct order

Activity