OS

OS

1. Goals

   • Execute user programs, make solving user problems easier
   • Make the computer system convenient to use
   • Use the computer hardware in an efficient manner

2. Definition

   • Resource allocator
     • Efficient and fair resource use
   • Control program
     • Prevent errors and improper use

3. Computer Startup

   • Bootstap program loaded
     • Stored in ROM/EPROM
     • Firmware
     • Initializes all aspects of system
     • Loads OS kernel and starts execution

4. Common Functions of Interrupts

   • Interrupt vector
     • Contains the addresses of all the service routines
   • Trap/Exception
     • Software-generated interrupt

5. Interrupt Handling

   • Polling
     • The interrupt controller must poll each device to determine which one made the request
   • Vectored
     • Request for attention from an I/O device has been received and also identifies the device