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Monday 8-9-2014Monday 8-9-2014

Class Requirements Earn hawk points today with the Name Game Network Login Information Website Login Requirements AUP Requirements Homework : PI’s

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© 2011 Pearson Education, publishing as Addison-Wesley

Class RequirementsClass Requirements

Purchase the AP Barron's AP Computer Science Level A Book.

Install BlueJ on your laptop or a computer at home. Create an email address to be used for this class. Webpage Link

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Name GameName Game

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Network Login InformationNetwork Login Information

Capitalize the first letter in the password

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Website LoginWebsite Login

5 points a day Save every submission

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AUPAUP

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HomeworkHomework

PI’s

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Hardware and SoftwareHardware and Software

Hardware• the physical, tangible parts of a computer• keyboard, monitor, disks, wires, chips, etc.

Software• programs and data• a program is a series of instructions

A computer requires both hardware and software

Each is essentially useless without the other

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CPU and Main MemoryCPU and Main Memory

CentralProcessing

Unit

MainMemory

Chip that executes program commands

Intel Pentium 4 orSun ultraSPARC III Processor

Primary storage area for programs and

data that are in active use

Synonymous with RAM

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Secondary Memory DevicesSecondary Memory Devices

Floppy Disk

Hard DiskMain

Memory

CentralProcessing

Unit

Secondary memorydevices providelong-term storage

Information is movedbetween main memoryand secondary memoryas needed

Hard disksFloppy disksZIP disksWritable CDsTapes

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Input / Output DevicesInput / Output Devices

Monitor

Keyboard

MainMemory

CentralProcessing

Unit

Floppy Disk

Hard Disk

I/O devices facilitate userinteraction

Monitor screenKeyboardMouseJoystickBar code scannerTouch screen

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Software CategoriesSoftware Categories

Operating System• controls all machine activities• provides the user interface to the computer• manages resources such as the CPU and memory• Windows XP, Windows 2000, Unix, Linux, Mac OS

Application program• generic term for any other kind of software• word processors, missile control systems, games

Most operating systems and application programs have a graphical user interface (GUI)

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Analog vs. DigitalAnalog vs. Digital

There are two basic ways to store and manage data:

Analog• continuous, in direct proportion to the data represented• music on a record album - a needle rides on ridges in the

grooves that are directly proportional to the voltages sent to the speaker

Digital• the information is broken down into pieces, and each piece

is represented separately• music on a compact disc - the disc stores numbers

representing specific voltage levels sampled at specific times

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Digital InformationDigital Information

Computers store all information digitally:• numbers• text• graphics and images• video• audio• program instructions

In some way, all information is digitized - broken down into pieces and represented as numbers

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Representing Text DigitallyRepresenting Text Digitally

For example, every character is stored as a number, including spaces, digits, and punctuation

Corresponding upper and lower case letters are separate characters

H i , H e a t h e r .

72 105 44 32 72 101 97 116 104 101 114 46

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Binary NumbersBinary Numbers

Once information is digitized, it is represented and stored in memory using the binary number system

A single binary digit (0 or 1) is called a bit

Devices that store and move information are cheaper and more reliable if they have to represent only two states

A single bit can represent two possible states, like a light bulb that is either on (1) or off (0)

Permutations of bits are used to store values

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Bit PermutationsBit Permutations

1 bit

01

2 bits

00011011

3 bits

000001010011100101110111

4 bits

00000001001000110100010101100111

10001001101010111100110111101111

Each additional bit doubles the number of possible permutations

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Bit PermutationsBit Permutations

Each permutation can represent a particular item

There are 2N permutations of N bits

Therefore, N bits are needed to represent 2N unique items

21 = 2 items

22 = 4 items

23 = 8 items

24 = 16 items

25 = 32 items

1 bit ?

2 bits ?

3 bits ?

4 bits ?

5 bits ?

How manyitems can be

represented by