OS

OS

1. Virtual Machine

   • Takes the code
     • Runs in Emulator
   • An emulation of a computer system

2. System Types

   • Real-time
     • Processes are handled almost immediately with precautions to ensure the processors don't fail so one piece of hardware doesn't cause any problems
   • Multi-user
     • Let's multiple people connect on one server system allowing the users to share resources
   • Multi-tasking
     • Schedules time allocation for the processor so it looks like everything is running simultaneously.
   • Embedded
     • Controls pre-programed commands on a processor built into the device
   • Distributed
     • Controls connected servers working together on the same or connected tasks

3. Interrupts

   • Polling
     • The processor checks every piece of hardware for new data and checks if they need attention. This wastes time as something that doesn't need attention wastes time if the hardware doesn't need it
   • Interrupts
     • The hardware that needs attention sends a signal to the processor so the processor can take it's data.
     • Causes:
       • CTRL + ALT + DELETE
       • Power/reset button
       • Corrupt memory
       • Arithmetic overflow
       • New Log in requests
       • Data transfers
       • Empty buffer
       • Illegal instruction

4. WIMP

   • Windows Icons Menus and Pointers

5. BIOS

   • Controls Bootstrap
     • Moves the OS to the memory when the computer boots up