Re: xwindow in oskit

To: danderse@cs.utah.edu, vhandel@chem.vu.nl
Subject: Re: xwindow in oskit
From: Kevin Van Maren <vanmaren@fast.cs.utah.edu>
Date: Mon, 16 Aug 1999 10:01:03 -0600 (MDT)
Cc: oskit-users@cs.utah.edu
Sender: owner-oskit-users@fast.cs.utah.edu

>   I had a quick look at the available documentation
> and code, and I must say that I immensely dislike the OSKit driver model
> on first sight.  The person who designed it seems to have been so focused
> on making a model that makes it easy to port existing drivers that it
> becomes a tremendous amount of work to write a driver "for the OSKit",
> without writing a huge amount of glue kludge.  So the easiest way to
> write a driver for the OSKit is to write a linux or freebsd driver
> and then to port it to the OSKit.  Has it never occured to anybody else
> that this might not be the ideal way to support drivers in an operating
> system ?  Or am I missing something ?

You are right, in that it is believed that the vast majority of
device drivers will come from other operating systems, rather
than being written `from scratch' for the OSKit.

Could you be more specific about the reasons you dislike the
driver model?

The OSKit driver model has two basic parts:
1) the osenv code that is used by the device driver to obtain access
to resources it needs (ie, memory, interrupts, etc), which has a
default implementation (for running on the `bare HW') in the dev
directory; and
2) the exported interfaces that are used by other parts of the OS/
application to access the device driver (this is a COM interface).

Yes, there is a bit of work involved to provide the top-half COM
interface wrappers for a device driver.  However, it isn't *that much*
work to implement the blkio interface, for a block device, or a
netio object for a network device.

Kevin Van Maren
University of Utah, CSL