February 25, 2008
Are Microkernels Hardware Abstraction Layers?
In a recent
post Gernot made a comparison between nanokernels and hardware
abstraction layers (HALs). This prompted a question on the
OKL4 developers mailing list: well, couldn’t you consider a microkernel a HAL?
.
I think the logical conclusion, both theoretical and practical, is a resounding, no.
Why? Well, a microkernel is, in theory (if not always in practise) minimal. That is, it should only include things in the kernel are those pieces of code that must run in privileged mode.
So, if a microkernel was to provide any hardware abstractions, it will only be providing the abstraction that have to be in the kernel. Which really falls short of a complete hardware abstraction layer.
Now, probably the more interesting question is should the
microkernel provide any hardware abstraction
, and if so what
hardware should it be abstracting
, and what is the right
abstraction
. After starting to write some answers to these
questions I reminded myself of the complexity involved in answering
them, so I will leave these questions hanging for another post.
Posted by Benno Leslie on February 25 at 01:01 PM
About Benno Leslie:
Benno Leslie, Vice President of Engineering at OK Labs holds a dual degree in Computer Engineering (with first-class honors) and Arts from UNSW. While at work, Benno does his best to avoid the marketing department, while he oversees a team of lead engineers and the customer support organization. When summer hits, the rugby field comes calling and Benno is either tackling others, out cycling, or letting loose at concerts.