Computer Systems Flashcards
(50 cards)
What is the Von Neumann architecture
Von Neumann put forward the stored program concept
A program must be resident in main memory to be executed
Program instructions are fetched, one at a time, from main memory and are executed, one at a time, in the CPU
What happens in secondary storage
hard disk drive ( programs and data are LOADED from the hard disk to RAM
What happens in primary storage
Primary storage - Main memory ( Programs and data are LOADED from the RAM to the processor)
What happens in the CPU
Central processing unit - CPU(Programs and processed data are transferred back from the processor to RAM) Main memory (Programs and data are finally transferred back from RAM to Secondary storage
Why is the Von Neumann architecture made as it is
To be as fast as possible with keeping costs low
What is the Harvard architecture
A Havard architecture computer has separate memory for program and instructions and for data.
Program instructions and data are transferred on a separate instruction and data bus respectively
Difference between Von Neumann architecture and Harvard architecture
Von Neumann - Shared memory (slower)
Havard - Separate memory (faster)
What is the special cycle that the Von Neumann architecture
Fetch-decode-execute cycle . CPU Fetches an instruction from Main Memory - Decode the instruction - Execute the instruction
What is the clock
Generates a signal that is used to synchronise the operation of the processor and the movement of data in the system
What is the control unit
controls and coordinates the fetch decode execution cycle of the processor. Directed by the timings of the system clock, i sends control signals to ensure that all the function of the different components of the processor are in the correct time with each other in the FDE cycle
What is the Arithmetic logic unit
Performs arithmetic and logic operations
Registers
- Super fast access memory in the processor(program counter, MAR,MDR,CIR, accumulator). Very small storage capacity
What is the program counter
Holds the memory address of the next instruction to be fetched from main memory. The value it stores increases by 1 at each FDE cycle
Memory Address register
Holds the address of the main memory location currently being accessed by the processor
Memory data register
Holds the data that is currently being processed
Accumulator
holds the results of calculations in the processor
Current instruction register (CIR)
Stores the instruction that is currently being processed
What are buses
Sets of wires that connect the internal components of a computer. They transmit signals (eg control signals,data signals) between the internal components of a computer
Types of buses
Address bus - Carries signals relating to memory between the CPU and main memory. Unidirectional
Data bus
Control bus
What is a CPU
A hardware component in a computer system with the function to process program instructions & data in the operation of the system.
What is computer architecture
Refers to the design & organisation of the components of the CPU and how they interconnect with the other components of the computer system.
What is the Von Newmann architecture
A computer system design where both program instructions & data are stored in the same main memory (i.e., shared storage in main memory).
What are buses
Sets of wires that connect the internal components of a computer.
What is the clock
It generates a signal that is used to synchronise the operation of the processor and the movement of data in the system.
