CST-091 Click your left mouse button to continue... © Delta College CST Faculty Module 1 Introduction to Computer Systems

CST-091CST-091

Click your left mouse button to continue . . .

© Delta College CST Faculty

Module Module 11

IntroductiIntroduction toon to

Computer Computer SystemsSystems

Input / Process / Output Input / Process / Output CycleCycle

Input OutputProcess

Storage

Data enters the computer.

In a payroll example, you key in 40 hours and a rate of $10.00 per hour.

The data is processed by the computer.

For example, the pay is 40 times 10.00 or $400.00

We need to see the answer – it is output.

For example, the $400.00 could be displayed.

We may want to store the results for end-of-year taxes.

The $400.00 could be stored on disk.

HardwareHardware

Physical parts of the computerPhysical parts of the computer The things you can “touch”The things you can “touch” The ProcessorThe Processor Input devicesInput devices Output devicesOutput devices Storage devicesStorage devices

ProcessProcess Using the data that is in memoryUsing the data that is in memory For example: CalculatingFor example: Calculating Processing HardwareProcessing Hardware

o Main MemoryMain Memoryo Central Processing UnitCentral Processing Unit

– Arithmetic/Logic UnitArithmetic/Logic Unit– Control UnitControl Unit

Main MemoryMain Memory Also Known As . . .Also Known As . . .

o Primary MemoryPrimary Memoryo Random Access Memory (RAM)Random Access Memory (RAM)

Holds program being runHolds program being run Holds data being processedHolds data being processed

BitsBits Memory made up of bitsMemory made up of bits BBinary Diginary Digitsits Small electronic componentsSmall electronic components Can be “On” or “Off”Can be “On” or “Off”

BitsBits

On --- has a value of 1On --- has a value of 1

Off --- has a value of 0Off --- has a value of 0

BitsBits

So memory is a bunch of one’s and zeros.So memory is a bunch of one’s and zeros.

1 1 111 00 0On Off Off OffOn On On On

ByteByte

A group of eight bits is called a byteA group of eight bits is called a byte So, this is a byte . . .So, this is a byte . . .

1 1 111 00 0

ByteByte

Look at these 40 bitsLook at these 40 bits

0100010001000101010011000101010001000001

Broken into groups of eights, they Broken into groups of eights, they become 5 bytesbecome 5 bytes

0100010001000101010011000101010001000001

The ASCII CodeThe ASCII Code

Each character is made up of 8 Each character is made up of 8 bits in a bytebits in a byte

So each byte contains a So each byte contains a charactercharactero A Number (0 1 2 3 4 5 … )A Number (0 1 2 3 4 5 … )o A LetterA Letter

– Upper Case (A B C … )Upper Case (A B C … )– Lower Case (a b c … )Lower Case (a b c … )

o A Special Character ($ # . , & … )A Special Character ($ # . , & … )


Each character has its own Each character has its own pattern of bits – in a code pattern of bits – in a code

The code that is used is called The code that is used is called ASCIIASCIIo AAmerican merican SStandard tandard CCode for ode for

IInformation nformation IInterchangenterchangeo Pronounced: “Ask-ee”Pronounced: “Ask-ee”


Look at these 5 bytesLook at these 5 byteso They contain 5 characters in ASCII CodeThey contain 5 characters in ASCII Codeo They happen to be upper-case lettersThey happen to be upper-case letters

0100010001000101010011000101010001000001

D E L T A

MemoryMemory

Measured in number of bytesMeasured in number of bytes K = KilobyteK = Kilobyte

o A “Kay”A “Kay”o A Thousand Bytes (1,000)A Thousand Bytes (1,000)

M = MegabyteM = Megabyteo A “Meg”A “Meg”o A Million Bytes (1,000,000)A Million Bytes (1,000,000)

MemoryMemory

So, if you have 16 “Meg” of RAMSo, if you have 16 “Meg” of RAMo You have 16,000,000 bytes of main You have 16,000,000 bytes of main

memory on your system!memory on your system! And, if your diskette is 1.4 MAnd, if your diskette is 1.4 M

o It can contain 1,400,000 characters!It can contain 1,400,000 characters!– (1.4 times 1,000,000 is 1,400,000)(1.4 times 1,000,000 is 1,400,000)

1. In the standard processing cycle of a computer, the step that happens first is __________.

A short quiz: Click on the best answer.

A Storage

B Input

C Output

D Process

?

1. In the standard processing cycle of a computer, the step that happens first is __________.A Storage

B Input

C Output

D Process

Whoops that’s wrong – please click here to try again.

1. In the standard processing cycle of a computer, the step that happens first is __________.A Storage

B Input

C Output

D Process

Good for you, you got that one right! Click FORWARD

2. Where does data have to be in order to be processed by the computer?

A short quiz: Click on the best answer.

A On the screen

B On the printer

C In RAM

D Next to the keyboard

?


A On the screen

B On the printer

C In RAM




A On the screen

B On the printer

C In RAM


Yes, data has to be in main memory before it can be processed.

3. How many bits are in a byte?

Click on the best answer.

A 1

B 2

C 4

D 8

?


A 1

B 2

C 4

D 8



A 1

B 2

C 4

D 8

Yes, each byte has 8 bits.

4. If a bit is “ON,” it has the value __________.


A 0

B 1

C 8

D 1K

?


A 0

B 1

C 8

D 1K



A 0

B 1

C 8

D 1K

Yes, an “ON” bit has a value of 1 and an “OFF” bit has a value of 0.

5. What is the code used to represent characters in a PC’s memory?


A Bit-Byte

B IBM

C ASCII

D Mega-K

?


A Bit-Byte

B IBM

C ASCII

D Mega-K



A Bit-Byte

B IBM

C ASCII

D Mega-K

Yes, the American Standard Code for Information Interchange.

6. Which is larger?


A 1M

B 720K

?

6. Which is larger?

A 1M

B 720K


6. Which is larger?

A 1M

B 720K

Yes, 1M is 1,000,000 bytes and 720K is only 720,000 bytes

7. How many bytes are needed to hold this: CST-091


A 1

B 6

C 7

D 8

?


A 1

B 6

C 7

D 8



A 1

B 6

C 7

D 8

Yes, there are 7 characters so 7 bytes are needed.

DataData

Raw facts you want to process and Raw facts you want to process and turn into meaningful informationturn into meaningful information

Data can be:Data can be:o NumbersNumbers 1 2 3 4 5 …1 2 3 4 5 …o LettersLetters A B C … a b c …A B C … a b c …o Special Characters $ & ! , ( ) …Special Characters $ & ! , ( ) …

InputInput

Entering data into the computer’s Entering data into the computer’s main memorymain memory

Translating data into a form the Translating data into a form the computer can understandcomputer can understand

Input devicesInput deviceso KeyboardKeyboardo MouseMouse

Input: The KeyboardInput: The Keyboard

Alphabetic keys like typewriterAlphabetic keys like typewriter Number keysNumber keys

o Across the TopAcross the Topo On Special Keypad on Right SideOn Special Keypad on Right Side

Special CharactersSpecial Characterso Often Upper Case of Other KeysOften Upper Case of Other Keys

Input: The MouseInput: The Mouse

A Pointing DeviceA Pointing Device Controls position of pointer on Controls position of pointer on

screenscreen Pointer appears as different objects Pointer appears as different objects

depending on what you are doingdepending on what you are doingo Arrow (pointing or selecting)Arrow (pointing or selecting)o Hand (pointing or selecting)Hand (pointing or selecting)o Hourglass (waiting)Hourglass (waiting)o etc.etc.

Basic Mouse Basic Mouse TechniquesTechniques

1.1. CLICKINGCLICKINGo Move pointer to item on screen & Move pointer to item on screen &

press/release left mouse button oncepress/release left mouse button once


2.2. DOUBLE-CLICKINGDOUBLE-CLICKINGo Point at item & press/release left Point at item & press/release left

mouse button twicemouse button twice


3.3. DRAGGINGDRAGGINGo Point at item, hold left mouse button Point at item, hold left mouse button

down while dragging to new location – down while dragging to new location – let mouse button uplet mouse button up


4.4. RIGHT-CLICKINGRIGHT-CLICKINGo Move pointer to item on screen & Move pointer to item on screen &

press/release right mouse button press/release right mouse button onceonce

OutputOutput

Presenting informationPresenting information We see the data that We see the data that

is in the computeris in the computer Output devicesOutput devices

o ScreenScreeno PrinterPrinter

Output: The ScreenOutput: The Screen

Also Known As:Also Known As:o MonitorMonitoro DisplayDisplayo CRT (Cathode Ray Tube)CRT (Cathode Ray Tube)

Displays:Displays:o Data being keyed inData being keyed ino Info from program processingInfo from program processing

Output: The PrinterOutput: The Printer

Prints info out on paper from Prints info out on paper from computercomputer

Called “Hard-Copy”Called “Hard-Copy” For Example:For Example:

o Non-impact Printer: Ink Jet PrinterNon-impact Printer: Ink Jet Printer– Does not strike the paperDoes not strike the paper– Can be colorCan be color

o Laser PrinterLaser Printer– Very High QualityVery High Quality

StorageStorage

Main StorageMain Storageo Holds program being runHolds program being runo Holds data being processedHolds data being processedo In the System UnitIn the System Unito Is VolatileIs Volatile

– Needs steady supply of electricity to Needs steady supply of electricity to keep its contentskeep its contents

– Pull the plug – start over!Pull the plug – start over!

StorageStorage

Secondary StorageSecondary Storageo ““Auxiliary Storage”Auxiliary Storage”

– Hard DiskHard Disk– In System UnitIn System Unit

– DisketteDiskette– PortablePortable

o Holds programs and data when not Holds programs and data when not being usedbeing used

Secondary StorageSecondary Storage

Hard DiskHard Disko ““Fixed Disk”Fixed Disk”o Inside System UnitInside System Unito Large CapacityLarge Capacityo Holds:Holds:

– Operating SystemOperating System– ProgramsPrograms– DataData


3.5 Inch Diskette3.5 Inch Disketteo ““Floppy” or “Floppy Disk”Floppy” or “Floppy Disk”o PortablePortableo Relatively Small CapacityRelatively Small Capacity

– 1.4 M (1,400,000 bytes)1.4 M (1,400,000 bytes)

o Usually Holds DataUsually Holds Data– Can Transfer Data to Other SystemsCan Transfer Data to Other Systems


3.5 Inch Diskette3.5 Inch Disketteo Write-Protect SwitchWrite-Protect Switch

– Protect Data From ErasureProtect Data From Erasure

o Lower-Right Corner of BackLower-Right Corner of Back– Sliding Black Plastic SwitchSliding Black Plastic Switch– UP (Closed)UP (Closed)

– Can Read or WriteCan Read or Write

– DOWN (Open Square)DOWN (Open Square)– Can ReadCan Read– CAN’T Write!CAN’T Write!

ReadRead

WriteWrite

Not Not ProtectedProtected

Read Read OnlyOnly

Protected!Protected!

Suppose you are running a payroll Suppose you are running a payroll program on your computer.program on your computer.

The program will ask you for John The program will ask you for John Doe’s data – how many hours he Doe’s data – how many hours he worked and what his rate of pay is.worked and what his rate of pay is.

Once the program has John’s data, it Once the program has John’s data, it will calculate his pay.will calculate his pay.o For example, if John worked 40 hours at a For example, if John worked 40 hours at a

rate of $10.00 per hour, he has $400.00 rate of $10.00 per hour, he has $400.00 coming to him – before all the deductions coming to him – before all the deductions are taken out!are taken out!

Once John’s pay is calculated the Once John’s pay is calculated the program needs to print his check.program needs to print his check.

Also, the program needs to store Also, the program needs to store John’s pay information for later tax John’s pay information for later tax processing.processing.

Another Short Quiz …Another Short Quiz …

On the next few screens, you will On the next few screens, you will be presented with several steps be presented with several steps in the Input / Process / Output / in the Input / Process / Output / Storage cycle.Storage cycle.

Click in the diagram for the step Click in the diagram for the step you are in.you are in.

8. You are sitting at the computer with John Doe’s time ticket – and you need to get his data into the computer: his hours worked and his rate of pay. Click on the step you are in …

Another short quiz: Click on the best answer. ?

PROCESS

STORAGE

OUTPUTINPUT


PROCESS

STORAGE

INPUT OUTPUT

No – please click here to try again.


PROCESS

STORAGE

INPUT OUTPUT

YES! You are INPUTTING John’s data. Click FORWARD

Probably on the keyboard

9. Once John’s data is input, it is processed in the CPU by the payroll program. Once John’s pay has been calculated, his pay check is printed. Click on the step you are in now…

?

PROCESS

STORAGE

INPUT


OUTPUT


PROCESS

STORAGE

INPUT OUTPUT



PROCESS

STORAGE

INPUT OUTPUT

YES! The check is OUTPUT on the printer.

Pay Chec

k

By the way, which step would you be in if there was a problem with John’s data – for example, we tried to input –10 hours or he owed more on his deductions than he made? See my hint in the bottom left corner …

PROCESS

STORAGE

INPUT OUTPUT

The OUTPUT step: An error message would be displayed on the screen.

Error Message

10. Uncle Sam and the Governor want us to keep track of John’s pay – so he can pay the correct taxes at the end of the year. If we save John’s payroll data, which step are we in?


?

PROCESS OUTPUTINPUT

STORAGE


PROCESS

STORAGE

INPUT OUTPUT



PROCESS

STORAGE

INPUT OUTPUT

YES! You are STORING John’s data.Click FORWARD

Probably on the hard disk

SoftwareSoftware

Instructions that direct the Instructions that direct the operations of the computeroperations of the computer

A “Computer Program”A “Computer Program” Two Main CategoriesTwo Main Categories

o Application SoftwareApplication Softwareo System SoftwareSystem Software

Application SoftwareApplication Software

Performs specific tasks for youPerforms specific tasks for you Tasks are called “Applications”Tasks are called “Applications”

o Word ProcessingWord Processingo SpreadsheetSpreadsheeto DatabaseDatabaseo CommunicationsCommunicationso GraphicsGraphics

Systems SoftwareSystems Software

Programs that manage the Programs that manage the computer and its devicescomputer and its devices

Perform chores for youPerform chores for you The “Operating System”The “Operating System”

o e.g. Windowse.g. Windows

Systems SoftwareSystems Software

An Interface between you and An Interface between you and the computer hardwarethe computer hardware

An Interface between your An Interface between your application software and the application software and the computer hardwarecomputer hardware

The Operating SystemThe Operating System

An Interface between you (or An Interface between you (or your application) and the your application) and the computer hardwarecomputer hardware

Starts and Initializes the Starts and Initializes the computer (“booting”)computer (“booting”)

Coordinates system’s access to Coordinates system’s access to various devices (keyboard, various devices (keyboard, screen…)screen…)

11. What is another name for “Software?”


A System

B CPU

C Computer Program

D Processor

?


A System

B CPU

C Computer Program

D Processor



A System

B CPU

C Computer Program

D Processor

Yes, Software is a Computer Program.

12. Which kind of software controls the hardware?


A System Software

B Application Software

?


A System Software




A System Software


Yes, System Software controls the hardware for you.

13. Which kind of software does some work for you – that is, which kind performs tasks for you?


A System Software


?

13. Which kind of software does some work for you – that is, which kind performs tasks for you?A System Software



13. Which kind of software does some work for you – that is, which kind performs tasks for you?A System Software


Yes, Applications like Word Processing to create a letter.

© Delta College CST Faculty

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CST-091 Click your left mouse button to continue... © Delta College CST Faculty Module 1 Introduction to Computer Systems