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What Does Exokernel Mean?

Exokernel is a type of operating system developed at the Massachusetts Institute of Technology that seeks to provide application-level management of hardware resources. The exokernel architecture is designed to separate resource protection from management to facilitate application-specific customization.


Exokernels are typically small in size because of their limited operability.

Techopedia Explains Exokernel

Conventional operating systems always have an impact on the performance, functionality and scope of applications that are built on them because the OS is positioned between the applications and the physical hardware. The exokernel operating system attempts to address this problem by eliminating the notion that an operating system must provide abstractions upon which to build applications. The idea is to impose as few abstractions as possible on the developers and to provide them with the liberty to use abstractions as and when needed. The exokernel architecture is built such that a small kernel moves all hardware abstractions into untrusted libraries known as library operating systems. The main goal of an exokernel is to ensure that there is no forced abstraction, which is what makes an exokernel different from micro- and monolithic kernels.

Some of the features of exokernel operating systems include:

  • Better support for application control
  • Separates security from management
  • Abstractions are moved securely to an untrusted library operating system
  • Provides a low-level interface
  • Library operating systems offer portability and compatibility

The benefits of the exokernel operating system include:

  • Improved performance of applications
  • More efficient use of hardware resources through precise resource allocation and revocation
  • Easier development and testing of new operating systems
  • Each user-space application is allowed to apply its own optimized memory management

Some of the drawbacks of the exokernel operating system include:

  • Reduced consistency
  • Complex design of exokernel interfaces

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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.