Flashcards
SLR 4
Cards in this deck (31)
- 1What is a operating system + examplesThe low-level software that does the basic computers function such as scheduling tasks and controlling peripherals.
Microsoft Windows
Apple IOS
Google Android - 2What is a Operating System good at?What process is to be executed next
Allocating and managing memory
Using device drivers to talk with devices
Operating system provide a framework
Using protocols to other machines
Accepting and denying Security requests
User interface is fairly easy to understand - 3What is layering?Layers of a computer that only care about the layers above below them
The layers are:
User
Applications
Operating System
Hardware - 4What is Paging?Paging is processes and memory spaces divided into equal sized pages.
The pages can easily be slotted in and out of the RAM due to the equal sized pages - 5What is Segmentation?Processes are divided logically
decides if the content of the segment works when segmented
Processes are in different sizes
Segments may be harder to fit into gaps due to the different sizes - 6What is Virtual Memory?Used when RAM is full
Instructions which are not being used are moved to spare space in the hard disk then swapped back in when they are needed - 7What are the negatives of Virtual Memory?It may take more time to move instructions than executing them.
Causes disk thrashing which can slow down performance.
CPU can only execute instructions in the RAM. - 8How does an interrupt work?Device sends a signal if it deemed important
The fetch, decode, execute cycle checks if there is any interrupts
If there is, the CPU has to stop what it is doing and carry that out instead - 9How do Stacks work with Interrupt?Processes are stored on a stack.
Interrupts are popped into the stack and are executed before any other processes can start.
Interrupts with higher priority can interrupt another interrupt - 10What types of Interrupt are there?Hardware interrupts
Software interrupts
Input/Output interrupts - 11What does Scheduling do?Manages process that need to be executed.
Each process is given a slice of time which it can execute for.
Processes are stored in a queue.
Processes can be blocked if needed later.
Gives the illusion of multiple processes are running at the same time. - 12Give 4 Algorithms used to manage process queuesFirst Come First Serve
Shortest Job First
Round Robin
Shortest Remaining Time - 13What can block a process?Processes are blocked if they need a input or output request
- 14Why is there Multilevel feedback queues?They may have different priorities and algorithms
Algorithms can move processes from queue to queue as needed - 15Name the 5 types Of Operating SystemMulti-tasking operating systems
Multi-user operating systems
Distributed computer operating systems
Embedded operating system
Real-Time operating system - 16What does Multi-tasking operating systems do?When one processor can run other processes nearly at the same time
Allows for multiple applications to be running at once - 17What does Multi-user operating systems do?There may be many different users on one computer
Designed for the sharing of resources like files and programs - 18What does Distributed computer operating system do?Operating system coordinates computer across network like they were a single system
Used for factories or other industries - 19What is a Embedded operating system?Highly specialised for a specfic purpose
Small computer designed to fit into a machine or appliance
Washing machine - 20What does Real-Time operating system do?Ina safety critical environment
used when processes need to be executed within a time frame
Lots of redundancy in the system as it needs to be when there's an emergency - 21What is the BIOS?BIOS stands for Basic Input Output System.
Used in the ROM.
Fast to read and is non volatile.
Carries out instructions used to start the computer when it turns on. - 22What is the CMOS?CMOS stands for Complementary Metal-Oxide Semiconductor
Stores the BIOS - 23What is POST?POST stands for Power On Self Test.
When the computer is turned on the BIOS starts a POST.
It then uses this data to start the computer or show a warning message.
Prevents the BIOS from crashing in case of missing hardware. - 24What does the Kernel do?The Kernel manages the operations of the computer and the hardware such as memory and CPU time.
- 25What is the Bootstrap?A program that runs after the POST.
Loads the Kernel into the memory and hands over the computer.
The Kernel then loads the all the needed programs into the memory. - 26Explain what the Dual BIOS?Most modern computers have two BIOS's
A main one which carries out the main processes
A second one which restores the main BIOS if it fails - 27What does a Virtual Machine Do?A digital program which acts the same functionally as a physical device
Programs that run on virtual machine do know do not know they are on one - 28What is a Emulator?A program which acts like the native console of a video game, allowing it to be run on other computers
Allows PC's to run games which may be designed to run on a console - 29What do Virtual Servers do?They have a small number of physical servers with a number of virtual servers on them.
They operate the same as a physical server.
Known as virtualisation. - 30What is Interpret Intermediate Code?It complies its code into bytecode (intermediate code) which is easily translated by Java.
It means that the bytecode language can be used for different devices.
Only the virtual machine needs to be adapted for different devices . - 31What is a device driver?Software that tells the Operating System how to communicate with another device.