1.2.1 Systems Software Flashcards
What are the two main types of software?
Systems Software and Applications software.
What different parts of systems software are there?
Operating systems.
Device Drivers.
Utilities.
What are the key functions of an OS?
- Providing a user interface (UI).
- Processor scheduling.
- Handling interrupts.
- Memory management.
- File management.
- Device management.
- Providing security.
What are the main types of UIs?
- CLI (command line interface).
- GUI (graphical user interface).
- Menu based.
- Natural language.
What is the kernel?
The Kernel is the very core of the OS with complete control over everything in the system. It is the first part of the OS to load after the bootloader.
What are the different categories of Operating Systems?
Multitasking, Multi-user, Embedded, Real-time and Distributed.
What is a multitasking operating system?
A type of system software that allows a computer to run multiple programs or tasks at the same time.
What is a multi-user OS?
Allows multiple users to use a system and its resources simultaneously.
What is a distributed OS?
Allows multiple computers to work together on a single task via a network.
What is an embedded OS?
One designed to run on devices that have a single or limited range of functions rather than general-purpose computers.
What is a real-time OS? (RTOS)
One designed to carry out actions within a guaranteed time even when left running for long periods.
What are the 2 methods of splitting up data when allocating memory?
- Segmentation.
- Paging.
What is Segmentation?
When memory is split into variable-sized blocks called segments.
What is Paging?
When memory is divided into fixed-sized blocks called pages.
What are the different types of Scheduling?
- First come first served.
- Dound robin.
- Shortest job first.
- Shortest time remaining.
- Multi-level Feedback Queues.
What is Polling?
When the CPU keeps checking each piece of software and hardware in turn to see if it needs attention.
What are interrupts?
An interrupt is a signal from a piece of software or hardware that tells the CPU that it need immediate attention. They are handled by ISRs (internet service routines).
Describe the process of an interrupt happening.
- The contents of the PC and registers are copied to the stack.
- The origin of the interrupt is identified so that the appropriate ISR is called.
- The relevant ISR can then be loaded by changing the PC to the address of where the ISR starts in memory.
- The ISR completes its execution.
- The previous values of the PC and other registers can be restores to the CPU and the previous program is resumed.
What happens when there are too many interrupts?
Stack overflow, possibly crashing the computer.
