Lecture 1 Flashcards
What are the steps of processing a program for the CPU?
Fetch: Retrieve an instruction from program memory
Decode: Break down the instruction into parts that have significance to specific sections of the CPU
Execute: Various portions of the CPU are connected to perform the desired operation
Write Back: Simply “writes back” the results of the execute step if necessary
What are processor (CPU) made of?
- Control Unit
- Execution Unit
- Register file
What is the job of the control unit?
It controls the execution of the instructions stored in the main memory. Fetch unit, decode unit and execute unit
What is the job of the Program Counter (PC)?
Keeps the address of the next instruction
What is the job of the Instruction Register (IR)?
Keeps the instruction being executed
What are the two hierarchies of memory?
Nonvolatile and volatile
What is nonvolatile memory?
- Does not lose its data stored when the system shuts down
- Does take long to fetch and store data (still fast), has higher memory capacity than volatile memory
What is volatile memory?
Primary memory e.g. Cache and Random Access Memory
What are the 3 types of primary storage?
Processor Registers, Cache memory and RAM
What does the Processors Register do?
Contains information that CPU needs to carry out the current instruction (Small amount and FAST)
What does the Cache memory do?
Special type of internal memory used by many CPUs to increase their performance or “throughput”(Medium amount, medium fast)
What is the job of the RAM?
Contains the programs that are currently being run and the data the programs are operating on (Large amount, slow)
What is the width of address?
Limits the amount of memory that a computer can access (64-bit is common)
What does the I/O subsystem contain?
The devices that the computer uses to communicate with the outside world and to store data
