Re: Ada OS based on Minix3

[Martin Krischik <krischik@users.sourceforge.net>]

Hi Georg,

Georg Bauhaus schrieb:
> Peter C. Chapin schrieb:
>> Martin Krischik wrote:
>>
>>> Now, if I wanted to create an OS I would not target real hardware at
>>> all. At least not in the beginning. I would probably implement the OS
>>> inside a VMware virtual machine.

>> What about targeting a hypervisor like Xen? If I understand correctly
>> (and I may not) that would separate the OS somewhat from the real
>> hardware and may help its portability in the long run.

> How could separation from the hardware do better than a
> Microkernel such as Minix 3?

Speaking of Microkernel: what ever happened to the ring concept? Why
this all (ring 0) and nothing (ring 3) everywhere? After all one of the
most stable OS's - ever - used 4 privilege modes:

http://en.wikipedia.org/wiki/VAX#Privilege_Modes privilege mode.

Interesting to see that the File System runs in it's own mode -
especially when one considers the recent FUSE development.

Using 4 privilege modes certainly would be something I would investigate
when trying out OS design.

> Full virtualization also deprives you of access to
> a larger set of hardware. Which, I'd speculate, is not
> too helpful when targeting mostly embedded system?

Actually I see the "larger set of hardware" as a disadvantage for a new
OS. For a small OS with a few or only one developers the is just not
enough horse power to produce tons and tons of different device driver.

With full virtualization you just have one set of hardware to produce
device driver for which leaves you with more time for the interesting
things like new revolutionary OS design.

Regards

Martin
-- 
mailto://krischik@users.sourceforge.net
Ada programming at: http://ada.krischik.com