Changes between Version 42 and Version 43 of FAQ


Ignore:
Timestamp:
2016-08-18T14:00:27Z (8 years ago)
Author:
Jakub Jermář
Comment:

Do justice to the original motivation for having microkernels: extensibitliy

Legend:

Unmodified
Added
Removed
Modified

  • FAQ

    v42 v43  
    66=== What is a microkernel? ===
    77
    8 In a microkernel operating system certain functionality such as device drivers, file systems and networking is moved out from kernel space to user space. Code taken out of the kernel runs as a normal user process or processes. The microkernel itself provides only minimal functionality that is necessary for user processes to run and communicate. This strongly contrasts with the traditional monolithic operating systems that keep most of these functions inside the kernel. The main rationale for designing operating systems along the microkernel lines is that a bug in a kernel driver of a monolithic operating system usually results in the crash of the entire system whereas a bug in a user space driver of a microkernel operating system is confined to the user process in which the driver runs.
     8In a microkernel operating system certain functionality such as device
     9drivers, file systems and networking is moved out from the kernel space to
     10the user space.  Code taken out of the kernel runs as a normal user process
     11or processes. The microkernel itself provides only minimal functionality
     12that is necessary for user processes to run and communicate. This
     13strongly contrasts with the traditional monolithic operating systems
     14that keep most of these functions inside the kernel. The main rationale
     15for constructing operating systems along the microkernel design lines has been
     16achieving greater extensibility by forcing most of the operating
     17system policies into the user space parts and leaving the microkernel
     18itself free of policies as much as possible. This makes it possible to use different operating
     19system personalities, potentially even in parallel, on top of the same
     20microkernel and easily change functionality that would have otherwise been
     21hardcoded in the operating system kernel. Note that multiserver
     22microkernels bring the additional benefit of a limited fault-tolerance:
     23a bug in a kernel driver of a monolithic operating system usually
     24results in the crash of the entire system whereas a bug in a user space
     25driver of a microkernel operating system is confined to the user process
     26in which the driver runs.
     27 
    928
    1029=== What is a multiserver? ===