Today’s Topics Today’s Topics Chapter 6: System Unit Chapter 6: System Unit Chapter 7: Input/Output and Chapter 7: Input/Output and Storage Storage
Today’s TopicsToday’s Topics
Chapter 6: System UnitChapter 6: System Unit Chapter 7: Input/Output and StorageChapter 7: Input/Output and Storage
Chapter 6Chapter 6System UnitSystem Unit
How Computers Represent DataHow Computers Represent Data
Bit (Binary Digit): smallest unit of information that Bit (Binary Digit): smallest unit of information that a computer can work with (0 or 1)a computer can work with (0 or 1) Kilobits Per Second (Kbps) = 125 charactersKilobits Per Second (Kbps) = 125 characters Megabits Per Second (Mbps) = 125 pagesMegabits Per Second (Mbps) = 125 pages Gigabits Per Second (Gbps) = 125,000 pagesGigabits Per Second (Gbps) = 125,000 pages
Byte: one unit of storage consisting of 8 bitsByte: one unit of storage consisting of 8 bits Kilobyte (K or KB) = 1 pageKilobyte (K or KB) = 1 page Megabyte (M or MB) = 1,000 pagesMegabyte (M or MB) = 1,000 pages Gigabyte (G or GB) = 1,000 booksGigabyte (G or GB) = 1,000 books Terabyte (T or TB) = 1 million booksTerabyte (T or TB) = 1 million books
Decimal Number SystemDecimal Number System
6 = (6 x 10^0)6 = (6 x 10^0) 45 = (4 x 10^1) + (5 x 10^0) = 40 + 545 = (4 x 10^1) + (5 x 10^0) = 40 + 5 214 = (2 x 10^2) + (1 x 10^1) + (4 x 10^0) 214 = (2 x 10^2) + (1 x 10^1) + (4 x 10^0)
= 200 + 10 + 4= 200 + 10 + 4
Binary to Decimal ConversionBinary to Decimal Conversion
0 = (0 x 2^0) = 00 = (0 x 2^0) = 0 1 = (1 x 2^0) = 11 = (1 x 2^0) = 1 10 = (1 x 2^1) + (0 x 2^0) = 2 + 0 = 210 = (1 x 2^1) + (0 x 2^0) = 2 + 0 = 2 11 = 11 =
(1 x 2^1) + (1 x 2^0) = 2 + 1 = 3(1 x 2^1) + (1 x 2^0) = 2 + 1 = 3 101011 = 101011 =
(1 x 2^5) + (0 x 2^4) + (1 x 2^3) + (0 x 2^2) + (1 x 2^5) + (0 x 2^4) + (1 x 2^3) + (0 x 2^2) + (1 x 2^1) + (1 x 2^0) = 32 + 0 + 8 + 0 + 2 + 1 = (1 x 2^1) + (1 x 2^0) = 32 + 0 + 8 + 0 + 2 + 1 = 4343
Decimal to Binary ConversionDecimal to Binary Conversion
2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 =2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 = 128 64 32 16 8 4 2 1128 64 32 16 8 4 2 1 To convert a decimal number to binary, To convert a decimal number to binary,
first subtract the largest possible power of first subtract the largest possible power of two, and keep subtracting the next largest two, and keep subtracting the next largest possible power from the remainder, possible power from the remainder, marking 1s in each position where this is marking 1s in each position where this is possible and 0s where it is not. possible and 0s where it is not.
Decimal to Binary ConversionDecimal to Binary Conversion
2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 =2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 = 128 64 32 16 8 4 2 1 =128 64 32 16 8 4 2 1 = 0 0 1 1 0 1 1 10 0 1 1 0 1 1 1 5555 - 32 = 23 - 32 = 23 23 - 16 = 723 - 16 = 7 7 - 4 = 37 - 4 = 3 3 - 2 = 13 - 2 = 1 1 - 1 = 01 - 1 = 0
Character CodeCharacter Code
American Standard Code for Information American Standard Code for Information Interchange (ASCII): used for the InternetInterchange (ASCII): used for the Internet
Extended Binary Coded Decimal Extended Binary Coded Decimal Interchange Code (EBCDIC): used on IBM Interchange Code (EBCDIC): used on IBM mainframemainframe
Unicode: represents many foreign Unicode: represents many foreign languageslanguages
CPU SubcomponentsCPU Subcomponents
Control Unit: extracts instructions from memory Control Unit: extracts instructions from memory and decodes and executes themand decodes and executes them Machine Cycle or Processing CycleMachine Cycle or Processing Cycle
Instruction CycleInstruction Cycle Fetch: retrieves the next program instruction from memoryFetch: retrieves the next program instruction from memory Decode: determines what the program is telling the computer to Decode: determines what the program is telling the computer to
dodo Execution CycleExecution Cycle
Execute: performs the requested instructionExecute: performs the requested instruction Store: stores the results to an register or memoryStore: stores the results to an register or memory
Registers: Temporary Storage Locations in CPURegisters: Temporary Storage Locations in CPU Arithmetic-Logic UnitArithmetic-Logic Unit
CPU PerformanceCPU Performance
Data Bus: highway of parallel wires Data Bus: highway of parallel wires connecting CPU internal componentsconnecting CPU internal components
Word Size: maximum number of bits the Word Size: maximum number of bits the CPU can process at onceCPU can process at once
System Clock: electronic circuit that System Clock: electronic circuit that generates pulses at a rapid rate and generates pulses at a rapid rate and synchronizes the computer’s internal synchronizes the computer’s internal activities (GHz)activities (GHz)
Techniques to Improve CPU Techniques to Improve CPU PerformancePerformance
Superscalar Architecture: design of CPU Superscalar Architecture: design of CPU that can execute more than one instruction that can execute more than one instruction per clock cycleper clock cycle
Pipelining: processing technique that Pipelining: processing technique that feeds a new Instruction into CPU at every feeds a new Instruction into CPU at every step of processing cyclestep of processing cycle
Data Dependency: result of a completed Data Dependency: result of a completed instruction to process the next oneinstruction to process the next one
Techniques to Improve CPU Techniques to Improve CPU PerformancePerformance
Speculative Execution: processor executes and Speculative Execution: processor executes and temporarily stores the next instruction in case it temporarily stores the next instruction in case it proves usefulproves useful
Branch Prediction: processor tries to predict Branch Prediction: processor tries to predict what will likely happenwhat will likely happen
Example: IF A = B THEN Example: IF A = B THEN C = C + 1 C = C + 1
ELSE ELSE C = C - 1 C = C - 1
END IF END IF
Techniques to Improve CPU Techniques to Improve CPU PerformancePerformance
Parallel Processing: technique that uses Parallel Processing: technique that uses more than one processor running more than one processor running simultaneouslysimultaneously
MemoryMemory
Memory: chips that enable the computer to Memory: chips that enable the computer to retain informationretain information Random Access Memory (RAM): stores Random Access Memory (RAM): stores
information temporarilyinformation temporarily Read-Only Memory (ROM): prerecords Read-Only Memory (ROM): prerecords
instructions to start the computer and cannot instructions to start the computer and cannot be erasedbe erased
Cache Memory: stores frequently or recently Cache Memory: stores frequently or recently accessed program instructions and dataaccessed program instructions and data
Chapter 7Chapter 7Input/ Output and StorageInput/ Output and Storage
Input DevicesInput Devices
KeyboardKeyboard Insertion Point: the location of the cursor that Insertion Point: the location of the cursor that
shows where text will appear when you typeshows where text will appear when you type Toggle Key: the key that has only two Toggle Key: the key that has only two
positions which are on and offpositions which are on and off Example: Caps Lock KeyExample: Caps Lock Key
Function Keys: keys that provide different Function Keys: keys that provide different commands, depending on the program in usecommands, depending on the program in use http://www.compukiss.com/sandyclassroom/tutorialhttp://www.compukiss.com/sandyclassroom/tutorial
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Input DevicesInput Devices
KeyboardKeyboard Modifier Keys: the keys that have no effect unless Modifier Keys: the keys that have no effect unless
holding them down and pressing a second keyholding them down and pressing a second key Ctrl + ACtrl + A Ctrl + XCtrl + X Ctrl + CCtrl + C Ctrl + VCtrl + V Ctrl + HomeCtrl + Home Ctrl + EndCtrl + End Window + DWindow + D
Input DevicesInput Devices
MouseMouse TrackballTrackball Pointing StickPointing Stick Touch Pad (Track Pad)Touch Pad (Track Pad) JoystrickJoystrick Touch ScreenTouch Screen Light PenLight Pen StylusStylus Microphone Microphone ScannerScanner Bar Code ReaderBar Code Reader
Output DevicesOutput Devices
MonitorMonitor Liquid Crystal Display (LCD) / Flat-Panel Liquid Crystal Display (LCD) / Flat-Panel
DisplayDisplay High Definition Television (HDTV)High Definition Television (HDTV) Screen SizeScreen Size Resolution: sharpness of an imageResolution: sharpness of an image Refresh Rate: frequency at which the screen Refresh Rate: frequency at which the screen
image is updated in Hzimage is updated in Hz
Output DevicesOutput Devices
PrinterPrinter Inkjet Printer (Bubble-Jet Printer)Inkjet Printer (Bubble-Jet Printer) Laser PrinterLaser Printer PlotterPlotter
ProjectorProjector
StorageStorage
RAM VS StorageRAM VS Storage Storage devices are non-volatile: retaining Storage devices are non-volatile: retaining
data when the current is switched offdata when the current is switched off Storage devices are cheaper than memoryStorage devices are cheaper than memory Storage devices are important in system Storage devices are important in system
startup operationsstartup operations Storage devices are needed for outputStorage devices are needed for output
StorageStorage
Hard Disk DriveHard Disk Drive File Allocation Table (FAT): File Allocation Table (FAT):
table that keeps track the table that keeps track the location of files in MS Windowslocation of files in MS Windows
Partition: section of a disk Partition: section of a disk enabling computers to work enabling computers to work with more than one OSwith more than one OS
Internet Hard Drive: storage Internet Hard Drive: storage space on a server that is space on a server that is accessible from the Internetaccessible from the Internet
StorageStorage
Floppy Disk: 1.44 MBFloppy Disk: 1.44 MB Zip Disk: 750 MBZip Disk: 750 MB CD-ROM/ CD-R/ CD-RW: 650 MBCD-ROM/ CD-R/ CD-RW: 650 MB DVD-ROM/ DVD-R/ DVD-RW: 17 GBDVD-ROM/ DVD-R/ DVD-RW: 17 GB FMD-ROM: 1 TBFMD-ROM: 1 TB Solid-State Storage DevicesSolid-State Storage Devices
PC Card (PCMCIA)PC Card (PCMCIA) Flash Memory CardFlash Memory Card Smart CardSmart Card