Re: ExAmour

[Jean Louis]

* Richard Stallman <rms@gnu.org> [2020-06-23 07:01]:
> [[[ To any NSA and FBI agents reading my email: please consider    ]]]
> [[[ whether defending the US Constitution against all enemies,     ]]]
> [[[ foreign or domestic, requires you to follow Snowden's example. ]]]
> 
>   > https://github.com/remysaissy/examour-exokernel
> 
>   > >From what I understood It's an attempt to a GNU exokernel.
> 
> What would that mean?

>From Wikipedia: https://en.wikipedia.org/wiki/Exokernel

Exokernel is an operating system kernel developed by the MIT Parallel
and Distributed Operating Systems group,[1] and also a class of
similar operating systems.

1. https://pdos.csail.mit.edu/archive/exo/

Operating systems generally present hardware resources to applications
through high-level abstractions such as (virtual) file systems. The
idea behind exokernels is to force as few abstractions as possible on
application developers, enabling them to make as many decisions as
possible about hardware abstractions. Exokernels are tiny, since
functionality is limited to ensuring protection and multiplexing of
resources, which is considerably simpler than conventional
microkernels' implementation of message passing and monolithic
kernels' implementation of high-level abstractions.

Implemented applications are called library operating systems; they
may request specific memory addresses, disk blocks, etc. The kernel
only ensures that the requested resource is free, and the application
is allowed to access it. This low-level hardware access allows the
programmer to implement custom abstractions, and omit unnecessary
ones, most commonly to improve a program's performance. It also allows
programmers to choose what level of abstraction they want, high, or
low.

Exokernels can be seen as an application of the end-to-end principle
to operating systems, in that they do not force an application program
to layer its abstractions on top of other abstractions that were
designed with different requirements in mind. For example, in the MIT
Exokernel project, the Cheetah web server stores preformatted Internet
Protocol packets on the disk, the kernel provides safe access to the
disk by preventing unauthorized reading and writing, but how the disk
is abstracted is up to the application or the libraries the
application uses.