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From: "Robert L. Klungle" <bklungle@gte.net>
Subject: Re: From VERDIX to GNAT
Date: 2000/08/02
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stephane wrote:

> I have to evaluate the conversion of a large project from VERDIX/HP-UX to GNAT/Linux. My main problem seems to be how to replace VERDIX libraries by GNAT ones. I haven&#8217;t found any clue along this news group, can anybody help me?
>
> TIA
>
> Stephane.
>
> ------
> User of http://www.foorum.com/. The best tools for usenet searching.

I agree with Harry Overs.

I ported 73_000 lines from VERDIX SGI to Linux GNAT Intel.
I went directly to the Intel. In hind-sight, should have done it on SGI GNAT
first.

The three main problem areas were:
1. Record Representation Clauses (major drudgery, there were a lot of them).
2. Variant location in Variant records (simple fix once decoded the documentation.
3. Math Library (math.lib vs gnat's generics). Created package which instantiated
the generics wanted, and included it. Some function names different (e.g. asin vs
arcsin, etc).

Total port time was ~3 weeks.

Moving to Linux actually improved the situation dramatically.
The VERDIX Ada run time continually extended the dynamic memory
pool from the kernel, even though the program returned memory to
the pool during execution (there were no memory leaks). Eventually
the system ran out of memory and would crash (512MB system).
In talking to SGI and VERDIX, they said they did it for speed of the system.
Didn't expect anyone to run a system that had to stay up for days,
and sometimes weeks without reloading the program.

cheers...bob.