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Introduction to OSes

Introduction to OSes

OS purposes

  • Abstract the hardware
    • Both for convenient and portability
  • Multiplex
    • Of applications
  • Isolation
    • Between applications
  • Sharing
    • Like files on the machine
  • Security (Permission system / Access control system)
  • Performance
  • Range of uses

OS organization

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User Space: VI CC SH
-----------------------------
API-kernel (aka system calls)
  fd = open("out", 1) // `open` as a system call
                      // resides in the kernel.
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Kernel:  Processes   | FS
         Mem Alloc   |
         Access Crtl |
-----------------------------
Hardware:   CPU RAM DISK NET

Why hard/interesting

  • Unforgiving
  • Tension
    • efficient - abstract
    • powerful - simple
    • flexible - secure

QEMU is a hardware simulator. And we’ll use it accross the course.

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