Operating Systems: Three Easy Pieces Ch. 13

The abstraction: Address Space

• Early Systems
  • OS was a set of routines that sat in memory
  • Use the set of the memory
  • Multiprogramming and Time Sharing
    • Multiprogramming
    • Utilization
    • Efficiency
    • Time Sharing
    • Interactivity
    • Protection
  • The address space
    • easy to use abstract of physical memory
    • code
      • have to live in memory somewhere
    • stack
      • keep track of where it is in the function call chain
      • grow upward
    • heap
      • dynamic allocating memory
      • grows downward
    • The whole thing is just a convention
    • By putting stack and heap opposite, hopefully, grow well
    • What if Multiple threads co-exists → abstraction required
  • Virtualizing Memory
    • Transparency
      • Program should not be aware of the fact that memory is virtualized
      • OS does works to multiplex memory
    • Efficiency
      • OS strive to make the virtualization as efficient as possible
      • Both time and space
      • rely on hardware
    • Protection
      • make sure to protect processes from one another as well as the OS itself from processes
      • Property of isolation -