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Transcript of © 2011 Pearson Education, publishing as Addison-Wesley Monday 8-9-2014 Class Requirements Earn...
© 2011 Pearson Education, publishing as Addison-Wesley
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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© 2011 Pearson Education, publishing as Addison-Wesley
Name GameName Game
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© 2011 Pearson Education, publishing as Addison-Wesley
Network Login InformationNetwork Login Information
Capitalize the first letter in the password
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© 2011 Pearson Education, publishing as Addison-Wesley
Website LoginWebsite Login
5 points a day Save every submission
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© 2011 Pearson Education, publishing as Addison-Wesley
AUPAUP
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© 2011 Pearson Education, publishing as Addison-Wesley
HomeworkHomework
PI’s
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© 2011 Pearson Education, publishing as Addison-Wesley8
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
© 2011 Pearson Education, publishing as Addison-Wesley9
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
© 2011 Pearson Education, publishing as Addison-Wesley10
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
© 2011 Pearson Education, publishing as Addison-Wesley11
Input / Output DevicesInput / Output Devices
Monitor
Keyboard
MainMemory
CentralProcessing
Unit
Floppy Disk
Hard Disk
I/O devices facilitate userinteraction
Monitor screenKeyboardMouseJoystickBar code scannerTouch screen
© 2011 Pearson Education, publishing as Addison-Wesley12
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)
© 2011 Pearson Education, publishing as Addison-Wesley13
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
© 2011 Pearson Education, publishing as Addison-Wesley14
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
© 2011 Pearson Education, publishing as Addison-Wesley15
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
© 2011 Pearson Education, publishing as Addison-Wesley16
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
© 2011 Pearson Education, publishing as Addison-Wesley17
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
© 2011 Pearson Education, publishing as Addison-Wesley18
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