Re: ISO/IEC 14519 - Ada POSIX binding

[Marin David Condic <nobody@noplace.com>]

Ludovic Brenta wrote:
> 
> 
> POSIX has been around for a long time now, and yes, people do rely on
> it.  The revision process is long and thorough, much like the Ada
> standard's.
>  
I think yuou missed my point. If "Standard X" cites "Standard Y" and 
there is any change to "Standard Y", then "Standard X" has a problem of 
being potentially out of date. It doesn't matter how long "Standard Y" 
has been around - it is a separate standard subject to its own updates, 
enhancements, etc. It would be better for "Standard X" to specify its 
needs in such a way that "Standard Y" might be one method of solving 
them, but not necessarily the only method.




> 
> POSIX stands for Portable Operating System Interface for uniX.  It
> defines only the API and its semantics, not how the API is
> implemented.  If there is an underlying POSIX-compliant operating
> system, then the implementation is trivial.  If there is an OS that is
> not POSIX-compliant, then the implementation is a thick binding to the
> OS.  For bare boards, there is of course a higher implementation cost.
> But I submit that:
> 
Yes, I know what POSIX is. I also know that not every operating system 
on the planet is POSIX-compliant. I also know that there are machines 
with no OS - presumably a sockets package would be an optional thing for 
implementations that didn't require it. I am not against POSIX - I just 
think that if Ada is going to have some kind of sockets package, it 
ought to abstract itself one layer away at least so that POSIX is not 
the only possible answer.


> 
> 
> On the contrary, as I said, POSIX _is_ an abstract interface, and
> implementations have some freedom in how they implement it.
>  
It is an "abstract interface" for a UNIX-like implementation. There are 
OS's besides UNIX and possibly in the next ten years or so that an Ada 
standard would have to live, there may be a bunch more non-UNIX 
operating systems out there. I have no objection to POSIX or UNIX - just 
suggesting that an Ada standard would do well to not dictate either 
POSIX or UNIX as the only possible answer.


> P.S. There is already an implementation of the POSIX standard
> available at no cost under the GPL.  It is called FLORIST and is
> maintained by ACT.  From what I understand, it is currently a thin
> binding to a POSIX-compliant underlying OS (including sockets), but
> providing alternative package bodies is probably feasible for all
> kinds of platforms.

I am aware of FLORIST. You'd have a problem getting FLORIST adopted as 
the Ada standard - primarily because it is vendor specific and GPL 
licensed. Other vendors will want an answer that does not put GNAT/ACT 
in the driver's seat. (Although this might be a moot issue. One has to 
wonder how many of the other Ada vendors have a vigorous interest in 
future Ada standards. Or are many of them looking at it as a cash-cow to 
be milked for whatever they can get and then move on to more profitable 
markets?)

MDC
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Marin David Condic
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