3.1 computer architecture Flashcards
role of CPU in comptuer
- processes instructions and data
- input into computer
- so result can be output
what is meant by a microprocessor
- type of integrated circuit
- contained on a single chip
components in CPU
units: ALU, CU
registers: PC, MAR, MDR, CIR, ACC
buses: address, data, control
purpose of ALU
carry out logical operations/arithmetic calcs on data
purpose of CU
- controls operation of memory, processor, input/output devices
- send read/write signals to coordinate FDE cycle
purpose of PC
stores address of next instruction to be fetched from memory
purpose of MAR
- store address of instruction
- copy, then send to MDR
purpose of MDR
- stores data from address received from MAR
- send data to CIR
purpose of CIR
- stores instruction
- CPU is currently decoding/executing
purpose of ACC
- hold temporary data
- during calculations
what are registers
- small, fast storage location
- temp hold data during processing
purpose of address bus
- unidirectional
- carry address of location in memory
purpose of data bus
- bidirectional
- carry data between CPU and other components
purpose of control bus
- bidirectional
- carry control signals form CPU to other components
describe FDE cycle
- PC contain address of next instruction to be fetched
- copied to MAR via address bus
- instruction of address copied to MDR via data bus
- instruction in MDR sent to CIR
- PC incremented by 1
- instruction decoded by CU, executed by ALU
what is the stored program concept
- instructions stored in main memory
- instructions fetched, decoded, executed by processor
- programs can be moved to and from main memory
what is an instruction set
- list of all commands that a CPU can process
- commands are in machine code
what is a system clock
- defines clock cycle
- that synchronises all computer operations
how does increasing clock speed affect performance of CPU
- processing speed increasing
- if too fast, operations unsynchronised (crash)
- overheating
what is cache
- stores copies of most frequently accessed memory locations
- much quicker to access than RAM (located within CPU itself)
how does increasing cache affect performance of CPU
- more data can be stored
- access faster
what are cores
- individual processing unit within CPU
how does increasing number of cores affect CPU performance
- better and faster (more instructions FDE at once)
- could slow down as communication between each core inc
- instructions need to be FDE in sequence
purpose of embedded system
used to perform a dedicated function
characteristics of embedded system
- small in size
- rugged OS
- lower cost
- use less power than general-purpose computer
what devices are embedded systems often used in
- domestic appliances
- cars
- security systems
