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Revision Computer Science - Coggle Diagram
Revision Computer Science
Storage
Primary
Virtual Memory
Virtual Memory is created in the hard drive
Virtual memory stores open apps and programs when ram is full
Virtual memory is needed when RAM is full
Virtual memory disappears when there is more space in RAM again
Ram and Rom
Read Only Memory
The store data and instructions but in ROM its the bios and startup.
Random Access Memory
Ram in volatile and Rom is non-volatile
Volatile means it loses data when turned off but non-volatile means that it doesn't
Seconday
Non-Volatile that stores data and programs for later retrieval.
Solid state is durable optical is portable, magnetic has moc=ving parts and
Hard drive, Flash drive, floppy disk, cd, and dvd.
Magnetic, Solid state and Optical
System Architecture
Cpu Components
ALU stands for the arithmetic logic unit
This does all of the calculations for the cpu
The CU stands for the control unit
This controls everything in the cpu
Von neumann architecture
MDR - Memory data register - Stores what was in the adresses
PC - Program counter - Counts what the next addresses it needs to got to is
MAR - Memory address register - Stores the address that it has been to
ACC - Accumulator - Stores result from the calculations of the ALU
FDE Cycle
Then the cpu decodes the data and instructions and so it can read it
The cpu then exacutes these instructions and does what it is meant to do.
The cpu sends a request and fetches data and instructions from the RAM
This happens over and over.
Factors
Cache memory is a storage device in the cpu that makes it easier to retrieve important data, increasing this makes the cpu run more smoothly
A cpu core reads processes and help the cpu, if the cpu has more than one core then it increases speed
Clock speed is how many pulses are done, If you increase the speed then your computer will run faster but if you decrease it the your computer runs slower
Embedded system
A system with a system with in it