Systems Architecture

Systems Architecture

1. The purpose of the CPU

   • The central processing unit carries out all the processing for the computer by carrying out all the instructions passed to it.
   • It is made up of billions of transistors that combine to build logic gates to process the data and instructions.
   • The purpose of the CPU is to process data. It is where all the searching, sorting,calculating and decision making takes place in the computer.
   • They work at an incredible speed, determined by the electronic clock.
     • This is a clock chip that uses a vibrating crystal to maintain a constant speed.
     • A modern PC works at 4GHz
   • The processor is continuously following the Fetch - Decode - Execute cycle

2. The Von Neumanns Architecture

   • Designed in 1945 by an American scientist working for the US military
   • It is the blueprint for the modern digital computer
   • The Von Neumanns Architecture describes a computer in which:
     • The data and program are both stored together in the same place in the computer
     • All instructions and data are stored as binary.

3. Von Neumann

   • Only applies to the stored program concept of computing.
   • An instruction fetch and a data operation cannot occur at the same time as they use the same bus. this is the Von Neumann bottleneck problem.
   • Busses are serial and one directional, this can slow the computer
   • Modern architecture uses the same memory for both program instructions and data