Re: ADA os talk

["Warren W. Gay VE3WWG" <ve3wwg@home.com>]

chris.danx wrote:

> "Tony Gair" <tonygair@kissmyspam.blueyonder.co.uk> wrote in message
> news:20010826235613.1b22c8c2.tonygair@kissmyspam.blueyonder.co.uk...
>>This is an area I've been watching for some time.
>>And I suspect a lot of people are interested in this too.....
>>I would be interested to know peoples strategies for getting one up and
> running and just to get the talk rolling heres my tuppence..
> 
>>Make a ada kernal and interface it to the rest of linux operating system
>> by using c interfaces and then start writing the filesystem, drivers and X
>> windows, blah blah....
> 
>>what do people think ???
> 
> There are two on going OS in Ada developments that I know of at the minute
> (of the Desktop variety).  AdaOS and my own -- Sorcerer.  Ada OS is
> seemingly stalled and my own progresses very slowly mainly due to two
> factors: my interest in a quality IDE in Ada which is in development and the
> learning curve involved in OS development.


There is at least one more being developed in France. The name of it
escapes me at the moment. I believe there are others, including
IIRC, one in Germany.


...

> My suggestion is to start designing and coding file system drivers...  You
> can design and code them almost immediately and if the project goes
> pear-shaped then at least you can make them available for other ppl to play
> with.  Start with a file and pretend it's an FS in itself, write a disk-like
> interface for manipulating the file, then write all the code on top of this.


I think a lot of people could benefit, just from seeing what has been
"done before". For example, the following site lists several research
papers on various O/S projects to date :

    http://www.cs.arizona.edu/people/bridges/oses.html

Its surprising to see how many ideas that you thought
were original, which already have been researched by
someone else ;-)

If you don't start there, you're quitely likely duplicate
some effort, and very certainly, won't learn from their
mistakes without expending considerable effort.

Since it is the "considerable effort" that kills most projects,
it seems that this should be the first step.

 
> At the same time, slowly begin to play with pmode or whatever it is on your
> target machine, and learn the concepts of OSes.  Only when you've learned
> about such things should you even think about designing the OS, never mind
> coding it.  And don't have more than 2 or 3 developers to start with.
> Anymore than that and the project is likely to go belly up.


I have begun looking at the exokernel designs recently. I

find them intriguing because their design is such that the kernel
is just a safe shell around the physical resources. Then you build
your abstraction layer on top of that. This helps to divide the
project into manageable components. It's main advantage is
that you can build several different abstractions on top of the
same "base". The following is a one good place to start:

    http://www.pdos.lcs.mit.edu/exo.html

It may be that there is an existing exokernel design that can be
used as a starting point for an Ada OS design. Later a fully
Ada "base" can then be developed if necessary, once some experience
has been gained at the "higher layers".
-- 
Warren W. Gay VE3WWG
http://members.home.net/ve3wwg