1. System Clock, clock speed, Word Length & Bus Width

2. System Clock A quartz controlled oscillator that supplies a timing signal at a fixed rate. It could be likened to someone clicking their fingers, everything happens at this rate. Every computer has its own systems clock.

3. System Clock, clock speed, Word Length & Bus Width System Clock The data and instructions are fetched, decoded and executed in time with the system clock. Instructions and data are processed in time to the system clock. InstructionData InstructionData 1 Hz2 Hz3 Hz4 Hz5 Hz A typical clock speed or clock frequency: (2400,000,000 cycles per second) Clock speed of the processor

4. System Clock, clock speed, Word Length & Bus Width System Clock Instructions and data are processed in time to the system clock. InstructionData InstructionData 1 Hz2 Hz3 Hz4 Hz5 Hz (2400,000,000 cycles per second) Processor Internal Bus Memory When transferring data or instructions between the processor and main memory, sometimes the internal bus speed slows a computer down.

5. System Clock, clock speed, Word Length & Bus Width Word Length Data is transferred in binary words. These represent the data and instructions in a computer system. (x8 bit binary word) Internal Bus Word Length (x16 bit binary word) (x24 bit binary word)

6. System Clock, clock speed, Word Length & Bus Width Bus Width Bus width refers to the number of signal wires or lines allocated to a bus. Direction of travel The number of lines in a bus What is the effect of bus width on binary word size?

7. System Clock, clock speed, Word Length & Bus Width Bus Width The effect of bus width on word size No. Of wires in bus No. Of bits in a word on the bus No. Of different binary words No. Of different binary words as a power of 2 Example of a binary word on the bus The largest word counting in denary 1122121 11 2242 103 3382323 1017 44162424 110015 882562828 11110001255 16 65,5362 16 1101101111110 000 65,353 20 1,048,5762 20...1,048,575 24 16,777,2162 24...16,777,215