Re: Ada OS Kernel features

[dmitry@elros.cbb-automation.de (Dmitry Kazakov)]

On Thu, 6 Sep 2001 19:06:29 +0100, "chris.danx"
<chris.danx@ntlworld.com> wrote:

>
>> > I really don't get why a driver must have access to system structures or
>> > atleast those in kernel space, can you explain this?
>>
>> A driver has access to raw hardware.  Therefore it necessarily has
>> access to the system -- it could rewrite the copy of the OS on disk
>> if it chose.
>
>Perhaps, but that's a problem that could be solved, in part, by restricting
>what the drivers allowed to access.  Video drivers have no business using
>the disk, so their access to disk access ports should be denied.  Similar
>schemes should be used when appropriate.  It should not be possible for a
>driver to access things willy nilly.

Any shared device should be not allowed to be directly used in the
user mode. If a video driver operates in the user mode, then it is
possible to have an application that reads and updates the parts of
the screen of another application. Now consider that another
application is a part of home-banking software. Wellcome in the
MS-Windows world!

Regards,
Dmitry Kazakov