1.1 Systems architecture

1.1 Systems architecture

1. 1.1.1 Architecture of CPU

   • CPU
     • Brain of the system
     • Decodes and executes instructions
   • 3 main components
     • Control Unit
       • Decodes instructions
       • Sends control signals to whole system
     • Arithmetic Logic Unit
       • Calculations
       • Logical Operations
     • Cache
       • Super fast memory on CPU
       • Holds frequently accessed data
   • Von Neumann
     • Fetch-Decode-Execute Instructions
     • 1 instruction at a time
   • Registers
     • Memory Address Register
       • Holds address of data/instruction
     • Memory Data Register
       • Holds data fetched or to be sorted
     • Program Counter
       • Holds address of next instruction
     • Accumulator
       • Holds results of calculations

2. 1.1.2 CPU Performance

   • Clock Speed
     • 1 hertz = number instructions per second
     • Higher clock speed = more instructions
   • Number of cores
     • Each core can process indenpendently
     • More cores = more instructions
   • Cache size
     • Data storage on CPU
     • Faster than RAM
     • Larger cache = more data

3. 1.1.3 Embedded systems

   • "A computer system often built into a larger machine. They have limited functions"
   • Characteristics
     • often control systems
     • monitor and control machines
     • easier to design
     • cheaper to produce
     • efficient at task
   • Examples
     • MP3
     • Washing machine
     • car headlights
     • plane autopilot