Introduction to Computing - Lecture 9

CSC 101Introduction to ComputingLecture 9Dr. Iftikhar Azim Niazianiaz@comsats.edu.pk1Last Lecture Summary 2Number SystemDecimalBinaryOctalHexadecimalNumber conversionBits and BytesBinary numbers are made of bitsBit represents a switchA byte is 8 bitsByte represents one character3Bit and Byte4Text CodesConverts letters, numbers, special symbols into binary numbersStandard codes necessary for data transferSame combinations of numbers to represent the same individual pieces of dataFour most popular codesEBCDICASCIIExtended ASCIIUnicode5EBCDICExtended Binary Coded Decimal Interchange Code8-bit code to represent 256 symbolsStill used in IBM mainframes and mid range computersRarely used in PCs6EDCDIC7ASCIIAmerican Standard Code for Information InterchangeMost popular and widely used character setUsed to represent English symbols7-bit code to represent 128 charactersFrom 0 to 12733 are non-printing control characters (now mostly obsolete)95 printable characters including space (invisible graphic character)8ASCII Codes9ASCII Code10Extended ASCII8-bit code that specifies the characters for values from 128 to 255. First 40 symbols represent pronunciation and special punctuation symbol128 to 167Remaining are for graphics and other symbols11Extended ASCII Code12Letter Conversion to Binary13UnicodeUnicode Worldwide Character Standard provides up to 4-bytes—32 bitsCan represent more than 4 billion characters or symbols232 = 1,073,741,832Enough for every unique character and symbol in the worldChinese, Korean and Japanese LanguagesCodes for special mathematical and scientific symbolsFirst 256 characters are same as ASCIICurrent version (Jan 2012) is 6.1Contains 110,181 characters from 100 different languages and scripts14Binary ArithmeticSimilar to arithmetic in decimal number systemOperations performedAdditionSubtractionMultiplicationDivision15Binary Arithmetici16Binary Arithmetici17Binary Arithmetici18Boolean AlgebraDescribes the relationship between the inputs and outputs of a digital circuitGeorge Boole, an English Mathematician in 1854 proposed the basic principles of algebraUses Variables and operationsBoolean variable has only two possible values0 or 1 or False or TrueBasic Logical operations areAND, OR and NOT19Basic Logical OperationsAND operationyields true in case when both of its operands are trueOR operationyields true in case when either or both of its operands are trueNOT operationUsed to invert the value of its operand20Logical OperationsTruth Table is a list of all possible input values and the output for each input combination21Logical Operations22Logical Operations23The System UnitThe system unit is a case that contains electronic components of the computer used to process data24The System UnitThe inside of the system unit on a desktop personal computer includes:Drive bay(s)Power supplySound cardVideo cardProcessorMemory25The System UnitThe motherboard is the main circuit board of the system unitA computer chip contains integrated circuits (IC)26Structure - Top LevelComputerMain MemoryInputOutputSystemsInterconnectionPeripheralsCommunicationlinesCentralProcessing UnitComputer27Structure - The CPUComputerArithmeticand Login UnitControlUnitInternal CPUInterconnectionRegistersCPUI/OMemorySystemBusCPU28Structure - The Control UnitCPUControlMemoryControl Unit Registers and DecodersSequencingLoginControlUnitALURegistersInternalBusControl Unit29CPUCentral Processing UnitBrain of the computerControl unitControls resources in computerInstruction setArithmetic logic unitSimple math operationsComparisons Logic operationsRegisters30Function of CPU31ALU OperationsRegisters32Movement of Instruction and Data33Machine CycleSteps by CPU to process dataInstruction cycleCPU fetches the instructionDecodes the instructionExecution cycleCPU performs the instructionStores the result (sometimes required)Million Instructions per second (MIPS)Billions of cycles per second (BIPS)34Machine CycleInstruction cycleExecution cycle35Steps In a Machine Cycle36Machine Cycle PipeliningPipeliningProcessor begins fetching a second instruction before it completes the machine cycle for the first instruction37Leading Processor Manufacturer3838MemoryVon Neumann ArchitectureConcept of stored programStores open programs and dataSmall chips on the motherboardMore memory makes a computer faster39Memory Address and SizeEach Memory has an addressMemory size is measured in KB, MB, GB or TB40What Memory Stores?Store Instructions waiting to be executed by the processorData needed by those instructions, andResults of processing the dataStores three basic categories of items:The operating system and other system softwareApplication programsData being processed and the resulting information41How Instruction Moves In and Out of Memory42SummaryHow Computer Stores DataText CodesEBCDIC, ASCII, Extended ASCII and UnicodeBinary ArithmeticBoolean AlgebraCentral Processing Unit (CPU)Control Unit and ALUMachine CycleMemory43SummaryHow Computer Stores DataText CodesEBCDIC, ASCII, Extended ASCII and UnicodeBinary ArithmeticBoolean AlgebraCentral Processing Unit (CPU)Control Unit and ALUMachine Cycle44