Unit 1.1 System Architecture

Unit 1.1 System Architecture

1. Von Neumann Architecture

   • Memory – Memory is used to store data currently being used and also stores the BIOS for the computer to be able to start up. Data and Addresses are transferred to the cpu using Data and Address Buses.
   • CU - The control unit is used to control the functions and operations of running on the CPU. The control unit also maintains the MAR and the MDR.
     • The MAR/Memory Address Register holds addresses previously given.
     • The MDR/Memory Data Register holds data that was previously given.
   • ALU - The Arithmetic Logic Unit is used for perform all arithmetic and logic operations on the CPU. Logic is where comparisons of numbers are made. Arithmetic is where mathematical calculations take place. The ALU will also need to use the accumulator.
     • Accumulator - The Accumulator remembers the results of previous calculations
   • one dedicated set of address and data buses for reading and writing to memory, and another set of address and data buses to fetch instructions.

2. Computer Components

   • CPU
     • The CPU is like the brain of the computer, it Fetches Decodes and Executes commands
   • Secondary Storage
     • A place to store and retrieve data long term
   • CPU Cooler
     • The CPU cooler just helps the CPU as it prevents heat damage on the CPU
   • Mother Board
     • Connects all components and allows them to Communicate with each other
   • Network card
     • Allows computers to connect to the Network
   • GPU
     • A GPU or Graphics Processing Unit is a programmable logic chip specialized for display functions. The GPU renders images, animations and video for the computer's screen. GPUs are located on plug-in cards
   • RAM/ROM Memory
     • RAM Random Access Memory RAM is considered volatile memory, which means that the stored information is lost when there is no power. it stores data that is currently running

3. CPU & Fetch Decode and Execute

   • Fetch - where it first locates and retrieves data
   • Decode - then decodes it into a larger uncompressed set of instructions
   • Execute - it then does what the instructions are telling it to
   • Fetch-Execute Cycle. First of all, both the data and the program that acts upon that data are loaded into main memory (RAM) by the operating system. The CPU is now ready to do some work.
   • progress counter - stores a value pointing to a location of the next instruction

4. Embedded Systems

   • Kettle, TV, Microwave
   • An embedde system is where there is a small control unit in a bigger item such as Microwaves

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