Phần cứng - Introduction to computing systems from bits và gates to C & beyond

Introduction to computing systemsfrom bits & gates to C & beyondyale n. patt & sanjay j. patel ©2001Chapter 1Welcome Aboard!Understanding Computer SystemsThree basic questions associated with understanding computing systems: What are computing systems used for? How are computing systems implemented? What are computing systems able to do and how well can they do it?3Computing Machines Ubiquitous ( = everywhere) General purpose: servers, desktops, laptops, PDAs, etc. Special purpose: cash registers, ATMs, games, telephone switches, etc. Embedded: cars, hotel doors, printers, VCRs, industrial machinery, medical equipment, etc. Distinguishing Characteristics Speed Cost Ease of use, software support & interface Scalability4This course is about:What computers consist ofHow computers workHow they are organized internallyWhat are the design tradeoffsHow design affects programming and applicationsHow to fix computersHow to build myself one real cheapWhich one to buyKnowing more about how a PentiumIII or PowerPC works internally5What is Computer Organization? a very wide gap between the intended behavior and the raw (unorganized) electronic devices.The forerunners to modern computers attempted to assemble the raw devices (mechanical, electrical, or electronic) into a separate purpose-built machine for each desired behavior.ElectronicDevicesDesiredBehavior6Role of General Purpose ComputersWe will break the gap into multiple levels and build an island in the middle.A general purpose computer is an island that bridges the gap between the desired behavior (application) and the raw material (electronic devices).ElectronicDevicesDesiredBehaviorGeneralPurposeComputercomputerorganizationsoftware7Two Important IdeasUniversal Computational DevicesGiven enough time and memory, all computers are capable of computing exactly the same things (irrespective of speed, size or cost).Turing’s Thesis: every computation can be performed by some “Turing Machine” - a theoretical universal computational device (not mathematically proven, but taken to be true).Problem TransformationThe ultimate objective is to transform a problem expressed in natural language into electrons running around a circuit!That’s what Computer Science and Computer Engineering are all about!8Problem Transformation - finer breakdownNatural LanguageAlgorithmProgramMachine ArchitectureDevicesMicro-architectureLogic CircuitsDesired Behavior:applicationRaw Material: electronic devices9Levels of DescriptionThese levels do not necessarily correspond to discrete components, but to predetermined (fixed) standard interfaces.Standard interfaces provideportabilitythird party software/hardwarewider usage These levels are to some extent arbitrary - there are other ways to draw the lines.Natural LanguageAlgorithmProgramMachine ArchitectureDevicesMicro-architectureLogic Circuits10The Program LevelMost computers run a special management program called the operating system (OS).Application programs interface to the machine architecture via the OS.An example:Application ProgramOperating SystemProgram (Software)This lecture PowerPointWindows NTDataApplication ProgramOperating System11The Machine LevelMachine ArchitectureThis is the formal specification of all the functions a particular machine can carry out, known as the Instruction Set Architecture (ISA)MicroarchitectureThe implementation of the ISA in a microprocessor - i.e. the way in which the specifications of the ISA are actually carried out.Logic CircuitEach element of the microarchitecture is composed of simple logic circuitsDevicesFinally, each logic circuit is actually built of electronic devices such as CMOS or NMOS or GaAs (etc.) transistors12Course Outline - What is Next?How to represent numbersThe building blocks of computers: logic gatesThe basic algorithm: the von Neumann modelAn example: the LC-2 structure and languageProgramming the machine: assembly languageA higher-level language: C 13