OS (Operating Systems)

OS (Operating Systems)

1. Types of operating systems :

   • iOS / Apple OS
   • Windows
   • Linux
   • Unix
   • Android
   • Chrome OS

2. What does it do?

   • Programmers do not need to worry about what hardware the user has
   • The OS takes care of the components used into the computer

3. What does the OS manage?

   • CPU
   • Multitasking
   • Interrupts
   • Memory
   • Backing Store
   • Peripherals
   • Security
   • Interface

4. Interrupts

   • Certain tasks are of high importance and therefore can't wait until the OS is able to allocate CPU time
   • The OS will manage interrupt requests.
     • ..Backing up existing processes so they can be resumed when the interrupt is finished
   • Interrupts can be triggered by hardware or software

5. Hardware and Software Interrupts

   • Hardware interrupts are triggered by hardware
     • when the mouse is moved
     • when a keyboard key is pressed
     • a game controllers stick is moved
   • Software interrupts
     • Software interrupts can be triggered by any application
     • The screen may need to be blanked for security reasons
     • A warning box needs to pop up when there is a fault

6. Drivers

   • Operating systems use device drivers to communicate to different peripherals
     • Perpiherals are devices that connect to a computer, such as a printer or game controller
   • A device driver maps the operating systems commands to the devices commands
     • For example, it contains the specific machine code needed to print a specific character on that brand of printer
       • each new hardware device will ship with a driver for common operating systems to ensure its compatibility

7. Security

   • OS have a range of security features
   • OS makes sure usernames and passwords are verified
   • And that the installed files will not damage the computer