Computer Architecture

• Computer Architecture


  The design and structure of a computer system
• Computer Organization


  The operational units and their interconnections that realize the architectural specifications
• IBM System/370 architecture was introduced in 1970
• IBM System/370 architecture


  • Included a number of models
  • Could upgrade to a more expensive, faster model without having to abandon original software
  • New models are introduced with improved technology, but retain the same architecture so that the customer’s software investment is protected
  • Architecture has survived to this day as the architecture of IBM’s mainframe product line
• Hierarchical system is a set of interrelated subsystems
• Structure


  The way in which components relate to each other
• Function


  The operation of individual components as part of the structure
• Four basic functions that a computer can perform

  • Data processing
  • Data storage
  • Data movement
  • Control
• Data processing


  Data may take a wide variety of forms and the range of processing requirements is broad
• Types of data storage

  • Short-term
  • Long-term
• Data movement


  Input-output (I/O) - when data are received from or delivered to a device (peripheral) that is directly connected to the computer<|>Data communications – when data are moved over longer distances, to or from a remote device
• Control


  A control unit manages the computer’s resources and orchestrates the performance of its functional parts in response to instructions
• Main structural components of the computer

  • CPU
  • Main Memory
  • I/O
  • System Interconnection
• CPU


  Controls the operation of the computer and performs its data processing functions
• Main Memory


  Stores data
• I/O


  Moves data between the computer and its external environment
• System Interconnection


  Some mechanism that provides for communication among CPU, main memory, and I/O
• Major structural components of the CPU

  • Control Unit
  • Arithmetic and Logic Unit (ALU)
  • Registers
  • CPU Interconnection
• Control Unit


  Controls the operation of the CPU and hence the computer
• Arithmetic and Logic Unit (ALU)


  Performs the computer’s data processing function
• Registers


  Provide storage internal to the CPU
• CPU Interconnection


  Some mechanism that provides for communication among the control unit, ALU, and registers
• Multicore Computer Structure


  Portion of the computer that fetches and executes instructions
• Core


  An individual processing unit on a processor chip
• Processor


  A physical piece of silicon containing one or more cores
• Cache Memory


  Multiple layers of memory between the processor and main memory
• Cache Memory


  • Is smaller and faster than main memory
  • Used to speed up memory access by placing in the cache data from main memory that is likely to be used in the near future
  • A greater performance improvement may be obtained by using multiple levels of cache
• Vacuum tubes were used for digital logic elements and memory
• IAS computer


  Fundamental design approach was the stored program concept
• First publication of the stored program concept idea was in 1945 for the EDVAC
• Design of the IAS computer began at the Princeton Institute for Advanced Studies and was completed in 1952
• First Generation of computers used vacuum tubes
• Transistors


  • Smaller
  • Cheaper
  • Dissipates less heat than a vacuum tube
  • Is a solid state device made from silicon
• Transistors were invented at Bell Labs in 1947
• It was not until the late 1950’s that fully transistorized computers were commercially available
• Second Generation Computers


  • More complex arithmetic and logic units and control units
  • The use of high-level programming languages
  • Provision of system software
• Third Generation: Integrated Circuits

  • 1958 – the invention of the integrated circuit
  • Discrete component
  • Single, self-contained transistor
• The two most important members of the third generation were the IBM System/360 and the DEC PDP-8
• Moore’s Law


  The density of elements on processor chips continues to rise
• IBM System/360 was announced in 1964