1.1 System Architecture

1.1 System Architecture

1. Processsor

   • "Brains of the computer"
   • Processes data, carries out instructions and executes them
   • GHz
     • 1 GHz= processor executes 1 billion instructions per second
     • 2 GHz = processor executes 2 billion instructions per second
   • Processors have a clock speed measured in Hertz (Hz)
     • Typical speeds have spanned between MHz and GHz
   • Processors can be multi core
     • Dual cores can carry twice as many instructions per second and they are independant
     • Dual cores, Quad cores and 8 cores
   • Processors have a cache which is really fast

2. Clock speed

   • Doubling the clock speed will double the number of instructions per second

3. Cores

   • Quadrupling the number of cores may quadruple the number of instructions executed per second

4. Cache size

   • Increasing cache size will reduce the number of memory disk transfers and this may speed up processing of these instructions

5. Embedded system

   • A computer system made up of both hardware and software (known as firmware)
   • Usually for very specialised

6. Internal components

   • Processor
   • main memory
     • RAM
       • Random Access Memory
       • Holds data and instructions CURRENTLY used by the processor
         • All is lost when power is turned off
       • Located on the mother board
         • Directly accessible by the processor
     • ROM
       • Read Only Memory
       • Instructions directly etched into ROM chip
       • When power is turned off, Instructions still remain
     • EEROM
       • Electronically Erasable Programmable Read Only Memory
       • Sim cards/Flash memory
       • Instructions/data can be erased electronically and replaced
   • I/O controllers
   • Buses

7. External components

   • Keyboard, Mouse, Printer, disk drives
   • I/O Devices/parts
   • Secondary storage

8. Fetch/Decode/Execute Intructions