Computer systems Flashcards
Define hardware
Physical component that makes up the computer.
Define software
Any program that runs on the computer.
What is system software?
Programs that are needed to enable the computer to function, including the operating system, utilities, library routines and programming language translators.
What is application software?
Programs that enable a user to perform a task.
What is managed in an operating system software?
- processors
- memory
- input/output devices
- applications
- security
What does processor management do?
Manages the use of the processor resources.
What does memory management do?
When a program is running it mut be in the computer’s main memory, and the OS must manage where in memory each program and data needs to go.
Give examples of input devices?
- a mouse
- a keyboard
- microphone
- sensor
Examples of output devices?
- speaker
- conventional computer screen
- an actuator
What does application management do?
When applications are installed an operating system will run a program to install it.
The OS will interact with applications through an Applications Program Interface (API).
What are methods in security management?
- passwords and different users
- Setting different access rights and privileges for different users
- Automatically downloading updates for the OS to ensure security loopholes are patched
- Encrypting files
What is in the Von Neumann architecture?
- the program is stored in main memory and instructions are fetched and executed sequentially
- there is a single memory (and bus system) for accessing both data and programmes
Function of ALU?
Arithmetic Logic Unit
- Logical Operations : boolean (AND, OR…)
- Shift operations: binary shift
- Arithmetic operations: addition, subtraction, multiplication, division
Function of Control Unit?
- controls execution of instructions in the same sequence
- decodes instructions
- regulates and controls processor timing using system clock
- sends and receives control signals to and from other devices within the computer
Function of clock?
Controls processor timing
Function of Bus?
Pass data between the components of the CPU.
Function of system bus?
Program instructions and data move between main memory and processor using internal connections called buses.
Describe the fetch-execute cycle
Fetch :
- address A of the next instruction is fetched from the register (a special fast memory location in the processor) where it is held
- This register is incremented so it points to the next instruction to be fetched
- Instruction at Address A is fetched from memory and put into a special register ready to be decodes
Decode:
- CU decodes the instruction to see what has to be done next
Execute:
- Instruction is execute
