1.2.1 Systems Software

1.2.1 Systems Software

1. Interrupts

   • Hardware
     • Memory parity error
     • Internal clock triggers suspending process
     • Shutdown to start triggered by user
   • Program
     • Arithmetic overflow
     • illegal instruction encountered in interpreted code
   • I/O
     • Buffer almost empy
     • Signals completion of data transfer

2. Scheduling Algorithms

   • First Come First Served (FCFS)
   • Shortest Job First (SJF)
   • Shortest Remaining Time (SRT)
   • Round Robin (RR)
   • Multi-level Feedback Queues (MFQ)

3. Operating Systems

   • Functions of an Operating System
     • Managing the processor
     • Managing the memory
     • Handling external periphals
     • Utility programs
     • Networking
     • Security
     • Providing a user interface
   • Types of Operating Systems
     • Distributed
     • Embedded
     • Multi-tasking
     • Multi-user
     • Real Time

4. Device Drivers

   • BIOS
     • POST
     • Boot Loader
     • Operating system kernal
   • Virtual machines
     • Emulation of a computer system // uses intermediate code

5. Memory Managment

   • Segmentation
     • divides memory into 'segments' // no set size
   • Paging
     • Divides memory into pages // set size
   • Page Table
     • Table to keep track of pages