Re: How do I go about creating a minimal GNAT runtime?

[anon@anon.org (anon)]

First, my comments was for 'Dimonax' not you. 

Second, you know that a minimal Ada runtime is also called an 'Embedded' 
Ada runtime system. And all Ada vendors including Adacore's GNAT have a 
package or a set of packages that can produce code for most 'Embedded' 
processors including the normal Intel processors (80386 to P4). This list 
could also, include (8088 to 80286) but those processors are limited in 
demand so you may have to pay extra.  As for GNAT the GNU GCC no longer 
support 8/16 bit code so GNAT does not support those type of processors.

This set of processor should now include the current set of processors like 
the Intel Core 2 processors series when they include the Ada 2005 specs. 
And in a few months they could include the Core i7 series aka (i786).


Now, as for your 

        ">No compiler can be good at *everything*." 

statement you forget assembly, which can do everything. It's problem is that 
it not that portable and most programmers prefer the ease of a high-level 
language.

All high-level languages like "C", Java" and even "Lisp" were never 
designed to write an operating system. But C is the main workhorse language 
for todays OS. And Sun built a "Net OS" they called "JAVAOS" which was 
written entirely in Java, they have since abandoned it. 

Then if you go back to the late 1970s and 1980s a few companies such as 
"TI" and "Symbolics" used "Lisp" to create a "Lisp" Computer where the 
processor was wired to used "LISP" functions as the processor language 
and the OS was written in 100% "LISP".

So should "Ada" become the next language for a OS using only Ada? Why not! 
It just that the people who are starting down this road should know that 
its not that easy. And they may have to rewrite the entire GNAT runtime 
system, if they use GNAT as the Ada compiler system or they should get
ready to pay big time if Adacore create a new GNAT runtime.



In <gohlb1$r6h$1@munin.nbi.dk>, "Randy Brukardt" <randy@rrsoftware.com> writes:
>"anon" <anon@anon.org> wrote in message 
>news:R7Bql.409687$Mh5.142056@bgtnsc04-news.ops.worldnet.att.net...
>> You need to understand what this person means by "minimal GNAT runtime"
>> system. From his web site, he means no Linux, Windows or other OS, aka
>> the Ada program is the OS and all libraries must be static.  That is,
>> until he creates a dynamic or shared library loader, but that means he
>> first must build a storage device driver with a file system.
>
>I understand exactly that. But you chose to ignore my point...
>
>> A problem with GNAT and this design is that GNAT uses around 50 packages 
>> ...
>
>....which is that GNAT is *not* designed for this sort of use. Yes, it can be 
>made to fit it, sort of, but it wasn't designed to minimize code size / 
>runtime size in the way that some other compilers (like Janus/Ada) were.
>
>The old saw "Patient: it hurts if I do X. Doctor: Don't do X." surely 
>applies here. If it is hard to do something with GNAT, use a more 
>appropriate tool. No compiler can be good at *everything*.
>
>....
>> All of this means it a big job.  This could help to explain why Adacores
>> charges $15K per years for someone to get those special runtime system
>> with GNAT PRO series.
>
>We used to have a bare-machine version of Janus/Ada, as did many other Ada 
>vendors, but they were all dropped due to lack of demand. Which is probably 
>why GNAT has a design that makes that hard - they didn't think it was that 
>important. It takes $$$ to show that sort of interest.
>
>                             Randy.
>
>