Operating System (CS - 308)
Chapter 2 - New Vocabulary

Hardware Protection

New Vocabulary Dual-mode operation
  • Dual-mode has two seperatemodes of operation:
  • I/O protection
    - Prevent any user program from directly controlling I/O devices.
    Memory protection CPU protection Bootstrap program Trap
    - A trap (or an exception) is a software-generated interrupt caused either by an error (for example, division by zero or invalid memory access), or by a specific request from a user program that an operating-system service be performed.
    System call
    - A request to operating system which is used to allow the user program to wait for I/O completion, if desired.  It is also called monitor call, a special operation that is executed by software for triggering an interupt.
    Volatile & nonvolatile
    - Main memory is a volatile storage device that lose its contents when power is turned off or otherwise lost.
    Seek time Rotational latency Cache
    - A memory buffer used to accommodate a speed differential is called a cache.
    Time slice