CPU and Memory Flashcards
What part of a computer is an electrical circuit that can perform calculations allowing it to carry out instructions?
Central Processing Unit
What can a CPU do?
Add binary
compare binary
store data in memory
What is the Von Neumann Architecture?
A computer design with stored (changeable) programmes
What are all the components of a CPU in a Von Neumann computer?
- a single control unit
- Arithmetic logic unit
- small amount of onboard cache
- internal clock
What is cache?
High speed memory that provides fast access to frequently used instructions and data.
What are the ‘wires’ in a computer called?
Buses
What three word cycle describes the process within a CPU?
fetch decode execute
What is an ALU?
Arithmetic Logic Unit- performs calculations and logical decisions.
What is a control unit?
Sends signals to control how data moves around the CPU.
What does an internal clock do?
It provides an internal pulse or heartbeat at a constant rate which synchronises the fetch-execute cycle
What does the main memory hold?
The data and instructions to be fetched and executed by the CPU.
What happens when you ‘fetch’?
Instructions fetched from main memory to the CPU through the bus.
What happens when you ‘decode’?
The instruction is decoded, so the CPU knows what to do
What happens when you ‘execute’?
Instruction is carried out. If it is a calculation or logical comparison: ALU does it. it may need to read/write data back into/from main memory
What characteristics can affect the performance of the CPU?
clock speed
Cache size
no. of cores
How does the clock speed affect the performance of the CPU?
faster the clock ticks - the more instructions you can process in a given amount of time
How does the cache size affect the performance of the CPU?
the bigger the cache size- more instructions and data can be stored in the cache-less time going back into the memory.
How does the number of cores affect the performance of the CPU?
more cores- the more instructions you can do simultaneously - however, some instructions cannot be split so doubling the no. of cores doesn’t always half the time.
What is ROM?
(read only memory) a small piece of memory containing the 1st instructions for the computer- to check the hardware is installed correctly and load basic input/output system. (the boot strap)
What is RAM?
(random access memory) temporary memory storage for programmes being executed by the processor.
Also, holds the operating system when the computer is running.
What is the name of the software stored onto ROM?
Firmware
What are the key differences between ROM and RAM?
RAM is volatile, you can read and write and is large.
ROM is non-volatile, read only and small.
What does volatile mean?
The contents are lost when the power is turned off.
What is an embedded system?
A computer system with a dedicated function within a larger (mechanical) system
