Computer organization and Architecture Chapter 1.pptx
- 2. Objectives • Know the difference between computer organization and computer architecture. • Understand units of measurement common to computer systems. • Appreciate the evolution of computers. • Understand the computer as a layered system. • Be able to explain the von Neumann architecture and the function of basic computer components.
- 3. 1.1 Overview (1 of 2) • Why study computer organization and architecture? – Design better programs, including system software such as compilers, operating systems, and device drivers. – Optimize program behavior. – Evaluate (benchmark) computer system performance. – Understand time, space, and price tradeoffs.
- 4. 1.1 Overview (2 of 2) • Computer organization – Encompasses all physical aspects of computer systems (e.g., circuit design, control signals, memory types). – How does a computer work? • Computer architecture – Logical aspects of system implementation as seen by the programmer (e.g., instruction sets, instruction formats, data types, addressing modes). – How do I design a computer?
- 5. 1.2 Computer Systems (1 of 2) • There is no clear distinction between matters related to computer organization and matters relevant to computer architecture. • Principle of Equivalence of Hardware and Software: – Any task done by software can also be done using hardware, and any operation performed directly by hardware can be done using software.* * Assuming speed is not a concern.
- 6. 1.2 Computer Systems (2 of 2) • At the most basic level, a computer is a device consisting of three pieces: – A processor to interpret and execute programs – A memory to store both data and programs – A mechanism for transferring data to and from the outside world
- 7. 1.3 An Example System (1 of 19) • Consider this advertisement:
- 8. 1.3 An Example System (2 of 19) • Measures of capacity and speed: – Kilo- (K) = 1 thousand = 103 and 210 – Mega- (M) = 1 million = 106 and 220 – Giga- (G) = 1 billion = 109 and 230 – Tera- (T) = 1 trillion = 1012 and 240 – Peta- (P) = 1 quadrillion = 1015 and 250 – Exa- (E) = 1 quintillion = 1018 and 260 – Zetta- (Z) = 1 sextillion = 1021 and 270 – Yotta- (Y) = 1 septillion = 1024 and 280 • Whether a metric refers to a power of ten or a power of two typically depends upon what is being measured.
- 9. 1.3 An Example System (3 of 19) • Hertz = clock cycles per second (frequency) – 1MHz = 1,000,000Hz – Processor speeds are measured in MHz or GHz. • Byte = a unit of storage – 1KB = 210 = 1024 Bytes – 1MB = 220 = 1,048,576 Bytes – 1GB = 230 = 1,099,511,627,776 Bytes – Main memory (RAM) is measured in GB. – Disk storage is measured in GB for small systems, TB (240 ) for large systems.
- 10. 1.3 An Example System (4 of 19) • Measures of time and space: – Milli- (m) = 1 thousandth = 10-3 – Micro- () = 1 millionth = 10-6 – Nano- (n) = 1 billionth = 10-9 – Pico- (p) = 1 trillionth = 10-12 – Femto- (f) = 1 quadrillionth = 10-15 – Atto- (a) = 1 quintillionth = 10-18 – Zepto- (z) = 1 sextillionth = 10-21 – Yocto- (y) = 1 septillionth = 10-24
- 11. 1.3 An Example System (5 of 19) • Millisecond = 1 thousandth of a second – Hard disk drive access times are often 10 to 20 milliseconds. • Nanosecond = 1 billionth of a second – Main memory access times are often 50 to 70 nanoseconds. • Micron (micrometer) = 1 millionth of a meter – Circuits on computer chips are measured in microns.
- 12. 1.3 An Example System (6 of 19) • We note that cycle time is the reciprocal of clock frequency. • A bus operating at 133MHz has a cycle time of 7.52 nanoseconds: • 133,000,000 cycles/second = 7.52 ns/cycle Now back to the advertisement ...
- 13. 1.3 An Example System (7 of 19)
- 14. 1.3 An Example System (8 of 19)
- 15. 1.3 An Example System (9 of 19) • Computers with large main memory capacity can run larger programs with greater speed than computers having small memories. • RAM is an acronym for random access memory. Random access means that memory contents can be accessed directly if you know its location. • Cache is a type of temporary memory that can be accessed faster than RAM.
- 16. 1.3 An Example System (10 of 19)
- 17. 1.3 An Example System (11 of 19)
- 18. 1.3 An Example System (12 of 19)
- 19. 1.3 An Example System (13 of 19)
- 20. 1.3 An Example System (14 of 19) • Serial ports send data as a series of pulses along one or two data lines. • Parallel ports send data as a single pulse along at least eight data lines. • USB, Universal Serial Bus, is an intelligent serial interface that is self-configuring. (It supports “plug and play.”)
- 21. 1.3 An Example System (15 of 19)
- 22. 1.3 An Example System (16 of 19)
- 23. 1.3 An Example System (17 of 19)
- 24. 1.3 An Example System (18 of 19)
- 25. 1.3 An Example System (19 of 19) • Throughout the remainder of the book you will see how these components work and how they interact with software to make complete computer systems. • This statement raises two important questions: – What assurance do we have that computer components will operate as we expect? – What assurance do we have that computer components will operate together?
- 26. 1.4 Standards Organizations (1 of 4) • There are many organizations that set computer hardware standards—to include the interoperability of computer components. • Throughout this book, and in your career, you will encounter many of them. • Some of the most important standards- setting groups include the following.
- 27. 1.4 Standards Organizations (2 of 4) • The Institute of Electrical and Electronic Engineers (IEEE) – Promotes the interests of the worldwide electrical engineering community. – Establishes standards for computer components, data representation, and signaling protocols, among many other things.
- 28. 1.4 Standards Organizations (3 of 4) • The International Telecommunications Union (ITU) – Concerns itself with the interoperability of telecommunications systems, including data communications and telephony. • National groups establish standards within their respective countries: – The American National Standards Institute (ANSI) – The British Standards Institution (BSI)
- 29. 1.4 Standards Organizations (4 of 4) • The International Organization for Standardization (ISO) – Establishes worldwide standards for everything from screw threads to photographic film. – Is influential in formulating standards for computer hardware and software, including their methods of manufacture. Note: ISO is not an acronym. ISO comes from the Greek, isos, meaning “equal.”
- 30. 1.6 The Computer Level Hierarchy (1 of 7) • Computers consist of many things besides chips. • Before a computer can do anything worthwhile, it must also use software. • Writing complex programs requires a “divide and conquer” approach, where each program module solves a smaller problem. • Complex computer systems employ a similar technique through a series of virtual machine layers.
- 31. 1.6 The Computer Level Hierarchy (2 of 7) • Each virtual machine layer is an abstraction of the level below it. • The machines at each level execute their own particular instructions, calling upon machines at lower levels to perform tasks as required. • Computer circuits ultimately carry out the work.
- 32. 1.6 The Computer Level Hierarchy (3 of 7) • Level 6: The User Level – Program execution and user interface level – The level with which we are most familiar • Level 5: High-Level Language Level – The level with which we interact when we write programs in languages such as C, Pascal, Lisp, and Java.
- 33. 1.6 The Computer Level Hierarchy (4 of 7) • Level 4: Assembly Language Level – Acts upon assembly language produced from Level 5, as well as instructions programmed directly at this level. • Level 3: System Software Level – Controls executing processes on the system. – Protects system resources. – Assembly language instructions often pass through Level 3 without modification.
- 34. 1.6 The Computer Level Hierarchy (5 of 7) • Level 2: Machine Level – Also known as the Instruction Set Architecture (ISA) Level. – Consists of instructions that are particular to the architecture of the machine. – Programs written in machine language need no compilers, interpreters, or assemblers.
- 35. 1.6 The Computer Level Hierarchy (6 of 7) • Level 1: Control Level – A control unit decodes and executes instructions and moves data through the system. – Control units can be microprogrammed or hardwired. – A microprogram is a program written in a low-level language that is implemented by the hardware. – Hardwired control units consist of hardware that directly executes machine instructions.
- 36. 1.6 The Computer Level Hierarchy (7 of 7) • Level 0: Digital Logic Level – This level is where we find digital circuits (the chips). – Digital circuits consist of gates and wires. – These components implement the mathematical logic of all other levels.
- 37. 1.9 The von Neumann Model (1 of 8) • On the ENIAC, all programming was done at the digital logic level. • Programming the computer involved moving plugs and wires. • A different hardware configuration was needed to solve every unique problem type. – Configuring the ENIAC to solve a “simple” problem required many days labor by skilled technicians.
- 38. 1.9 The von Neumann Model (2 of 8) • Inventors of the ENIAC, John Mauchley and J. Presper Eckert, conceived of a computer that could store instructions in memory. • The invention of this idea has since been described to a mathematician, John von Neumann, who was a contemporary of Mauchley and Eckert. • Stored-program computers have become known as von Neumann Architecture systems.
- 39. 1.9 The von Neumann Model (3 of 8) • Today’s stored-program computers have the following characteristics: – Three hardware systems: • A central processing unit (CPU) • A main memory system • An I/O system – The capacity to carry out sequential instruction processing. – A single data path between the CPU and main memory. • This single path is known as the von Neumann bottleneck.
- 40. 1.9 The von Neumann Model (4 of 8) • This is a general depiction of a von Neumann system: • These computers employ a fetch-decode- execute cycle to run programs as follows . . .
- 41. 1.9 The von Neumann Model (5 of 8) • The control unit fetches the next instruction from memory using the program counter to determine where the instruction is located.
- 42. 1.9 The von Neumann Model (6 of 8) • The instruction is decoded into a language that the ALU can understand.
- 43. 1.9 The von Neumann Model (7 of 8) • Any data operands required to execute the instruction are fetched from memory and placed into registers within the CPU.
- 44. 1.9 The von Neumann Model (8 of 8) • The ALU executes the instruction and places results in registers or memory.
- 45. 1.10 Non–von Neumann Models (1 of 2) • Conventional stored-program computers have undergone many incremental improvements over the years. • These improvements include adding specialized buses, floating-point units, and cache memories, to name only a few. • But enormous improvements in computational power require departure from the classic von Neumann architecture. • Adding processors is one approach.
- 46. 1.10 Non–von Neumann Models (2 of 2) • Some of today’s systems have separate buses for data and instructions. – Called a Harvard architecture • Other non-von Neumann systems provide special- purpose processors to offload work from the main CPU. • More radical departures include dataflow computing, quantum computing, cellular automata, and parallel computing.