*BSD News Article 57545


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From: nate@trout.sri.MT.net (Nate Williams)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: Now that 2.1 is out. What next?
Date: 21 Dec 1995 17:14:31 GMT
Organization: SRI Intl. - Montana Operations
Lines: 55
Message-ID: <4bc4ln$rkr@helena.MT.net>
References: <slrn4bl49t.9dt.coleman@redwood.skiles.gatech.edu> <4aqe32$tk@complete.org> <4avnda$skv@park.uvsc.edu> <wingDJvurC.G3s@netcom.com>
Reply-To: "Nate Williams" <nate@sneezy.sri.com>
NNTP-Posting-Host: trout.sri.mt.net

In article <wingDJvurC.G3s@netcom.com>, Ben Wing <wing@netcom.com> wrote:
>In article <4avnda$skv@park.uvsc.edu>,
[ Discussion about ELF binary format ]
>|Think of it as a new, incompatable way to make .o and .exe
>|files.
>
>I don't think this does justice to ELF.  The main reason the Linux
>folks switched from a.out to ELF was because creating shared libraries
>under the former was a major pain in the ass, but is relatively easy
>under the latter.
>
>What does FreeBSD use?  I would presume a.out, since it's a Berkeley
>thing, but maybe they use COFF.

We use a.out, but building shared libraries in the BSD's has *always*
been easy.  H.J. and I compared notes one day when he didn't understand
how FreeBSD built shared libraries, and it turned out that the *only*
difference in creating shlibs is one command line parameter was
different in Linux due to the necessity to keep old 'a.out'
compatability.  Otherwise the steps to creating shlibs were *exactly*
the same.  (Same commands, parameters, etc..)

> Either way, I don't think you can get the cool dynamic features of ELF.

True, but you have to have tools to support those features.  As of
today, none of the free OS's take advantage of the special features.

For the BSD's, changing just because something 'could' be done isn't a
good move.  If/when someone gets a complete toolset working and tested
*AND* there are some cool new toys which only work under ELF, it might
be worthwhile to also support ELF, but for now it would only add a
gratituous incompatability.

[ Story about SPARCworks tools deleted ]

>Apparently this whole business relies heavily on the ELF format,
>which was designed to allow for dynamic loading of code into a
>running program.

I've used it, and while I agree it's a good thing, I've also had it
back-fire on me and sometimes not do the right thing.  The intracasies
(sp?) of making sure everything that uses the original code can sometimes
bite you.  (Changing a function's parameter or return type causes all sorts
of fun errors. :)


Nate



-- 
nate@sneezy.sri.com    | Research Engineer, SRI Intl. - Montana Operations
nate@trout.sri.MT.net  | Loving life in God's country, the great state of
work #: (406) 449-7662 | Montana.
home #: (406) 443-7063 | A fly pole and a 4x4 Chevy truck = Heaven on Earth