eolas/zk/Basic_model_of_the_operating_system.md

1 KiB

tags
operating-systems
linux

Basic model of a *nix operating system

We can abstract the Linux OS into three operational levels or tiers, from the bottom up:

  • User processes: user space

    • The running programs that the kernel manages. Also known as the user space which is the memory that the kernel assigns for user processes. Comprising:
      • Graphical user interface
      • Servers
      • Shell
  • Kernel: kernel space

    • The core of the operating system. Software residing in memory that tells the CPU where to look for its next task. Acts as a mediator and primary interface between the hardware and the user processes. Known as kernel space: the memory that the kernel allocates for itself. Comprising:
      • System calls
      • Process management
      • Memory management
      • Device drivers
  • Hardware

    • The base: one or more CPUs and RAM memory performing computations and writing to memory. Comprising:
      • Processor (CPU)
      • Main memory (RAM)
      • Disks
      • Network ports