CPU and its elements Flashcards
what concept do computer systems follow
input, process, output, storage model
what does the CPU process?
data or instructions that are processed by the computer system in the process phase of the input, process, output, storage model
what is the CPU?
central processing unit - processes data by following instructions
how can data or information be accessed by the CPU?
any data or info that is to be saved or retrieved from some storage medium (eg. hard disk) has to first pass through the primary memory
what does the CPU contain?
control unit (CU)
arithmetic logic unit (ALU)
memory address register (MAR)
memory data register (MDR)
what is the control unit responsible for
operation of the CPU
what does the control unit control
retrieval of instructions from the primary memory
sequence of the execution of the instructions
what does the CU contain
various registers - MDR, MAR
what are registers
small storage location that can hold data
what is the ALU
performs all basic arithmetic, logical or input/output operation
what is the CU responsible for in terms of the ALU
providing the ALU with the data that needs to be processed, instructions of how the data should be processed
what does the MAR hold (2)
holds memory address of the data that is to be used by the ALU so that the ALU can fetch corresponding content from the memory and process it
holds memory address of where data that has been processed needs to be stored
how does the MAR communicate with primary memory
connects through memory address bus
what does the MDR hold
data that is to be used by the ALU and then saved onto the RAM
how is the MDR related to the MAR
the memory location that the MAR holds will be loaded onto the MDR to be processed by the ALU
what takes place in the MDR after processing
ALU places the result of processing onto the MDR
data is copied to the memory address location in RAM specified by the MAR
what connects MDR and RAM
data bus
what are busses
connecting wires that connect the CPU to other devices carrying instructions to/from components
built onto the motherboard
what are the three busses
data bus - links RAM to CPU (MDR)
control bus - links RAM to CPU (CU)
address bus - links RAM to CPU (MAR)
