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From: Philip Cummins <philip@no-spam.cs.uwa.edu.au>
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Subject: Re: AdaOS
Date: Wed, 07 Nov 2001 10:28:29 +0800
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Hello,

> Ah, yes, of course! We don't have device drivers any more, we have "Hardware
> Abstraction Layers".

You'd find it beneficial to have Hardware Abstraction Layers followed
by dynamically loadable device drivers. It is not a redundant academic
invention that is there to make life hard, but rather easier. A simple
search via Google will provide the sufficient documentation to back
this up.

For instance of a HAL operating is :

USB Hardware <-> USB HAL <-> USB Device Driver (ie, mouse, keyboard)

Essentially the USB HAL abstracts out a common front end API for the
USB device drivers to talk to the USB hardware which frequently changes
depending on which motherboard and chipset you're using. This removes
the need for each individual device driver to know what hardware it is
running off and hence redundant code.

PC