Re: GNAT Question

[cts@kampong.aedinc.net ((null))]

In article <7wLt6.19470$bL.1855137@news6-win.server.ntlworld.com>,
chris.danx <chris.danx@ntlworld.com> wrote:
>Hi,
>    Does anyone know if i can use GNAT to do OS work?  

Yes.  

Since you'll be working underneath the application/kernel boundary
you won't be able to use any parts of the gnats's built-in runtime
libraries that depend on the underlying OS.  You can either write
your own code to implement those parts of the runtime, or do without.
If you choose to do without (a reasonable choice for many situations)
you'll want to use 'pragma No_Run_Time'.  Look in the "GNAT User's 
Manual".



>Currently just starting work on it and we're
>implementing virtual FS support as a file on disk.  We're doing it in C via
>DJGPP but i hate C, 

BTW, If I were you, I'd use something other than DOS to do
the development work on.  Compiling in Unix and testing on a PC
simulator (such as Bochs) should help things go a lot smoother



>The info seems to suggest that you can't use
>GNAT, and the development of an Ada compiler for this kinda thing is needed.

Actually the reason they are building a compiler from scratch is
because the founder of that project (Nick Roberts) wants to write
an Ada compiler.  The reason he wants to write an operating system
is because he doesn't think any existing operating system nicely
supports Ada compilers.

In other words, he is creating the operating system to support the compiler; 
his compiler is not needed to write an operating system.  


Just curious, does anyone out there know about how many man-years
it might take to write an Ada compiler?  How long did it take for gnat?


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