Unit 4 Flashcards
Software
a set of programs that controls the hardware (application & system)
System software - a set of programs that allow the computer to function and allow the user to communicate with the computer
Application software - allows users to perform specific tasks, activities or work
Operating system & utility software (Type of system software)
Operating systems (OS) – a type of system software that manages computer hardware and application software
Utility software – type of system software designed to help maintain, enhance and troubleshoot/repair a computer system
Function of OS
- User-interface - how the user interacts with the operating system
A menu interface – single option chosen at each stage
A Graphical User Interface (GUI) - using windows, icons, menus and pointers
A Command Line Interface (CLI) - where commands are typed - File management – allocating space on secondary storage devices, managing the creation and deletion of files
- Memory management – loading programs from hard drive to memory
- Processor management - the process of controlling and allocating a computer’s central processing unit (CPU) resources to various tasks or processes running on a system
- Manage user accounts
- Multitasking
- Device management - managing the way peripherals (hardware) interact with software; using system software known as drivers to translate the OS instructions into commands specific hardware will understand
Firmware
very small piece of software, containing only the instructions required to access the secondary storage devices and start loading the operating system, is embedded in the computer’s ROM chip
E.g. Bootstrap, Boot loader
low-level control for the various basic aspects of a specific piece of hardware
Interrupts & process
SIGNAL FOR THE PROCESSOR’S ATTENTION, IT IS HANDLED BY OS
- Interrupt occurs: A signal tells the CPU that something needs attention.
- CPU checks interrupt register: The CPU looks at the interrupt register to identify the type of interrupt.
- Pause and save (stacking): The CPU saves its current state (like program counter, registers) onto the stack.
- Jump to Interrupt Service Routine (ISR): The CPU jumps to the specific Interrupt Service Routine (ISR) to handle the interrupt.
- Handle the interrupt: The ISR deals with the interrupt, like fixing a problem or processing data.
- Restore from stack (retrieving): Once done, the CPU retrieves its saved state from the stack.
- Resume original task: The CPU goes back to where it left off and continues its original task.
ISR/Interrupt register
ISR - Program with set of instructions to carry out the interrupt
IR- Where interrupts are stacked, checked after every FDE cycle
INterrupt examples
Hardware - power button pressed; power supply failure
User - keyboard pressed, moving mouse
Input/output - buffer nearly empty
Software - arithmetic overflow, new login request
Timer - screen recording, printer ink supply notification
