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Date: Mon, 10 Dec 2007 17:38:38 -0500
From: David Schultz <das@FreeBSD.ORG>
To: Alexander Leidinger <Alexander@Leidinger.net>
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Cc: Brooks Davis <brooks@FreeBSD.ORG>, Robert Watson <rwatson@FreeBSD.ORG>,
	freebsd-arch@FreeBSD.ORG
Subject: Re: RFC: libkse*.a in 7.0
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On Mon, Dec 10, 2007, Alexander Leidinger wrote:
> Running Solaris 8/9 programs is not supported by SUN on Solaris 10. It
> works in some cases, but it doesn't work in some other cases.

That's not true. It is supported. See:
    http://www.sun.com/software/solaris/programs/abi/
    http://www.sun.com/software/solaris/programs/abi/sag.xml

In theory, a SunOS 5.0 app will still work in SunOS 5.10.
Of course, in practice, perfect binary compatibility is too much
to ask for. It's possible to write programs that notice that
different releases aren't bug-for-bug compatible, and if you
statically link your binary or use unsupported ABIs, you break
their guarantee. But that's orthogonal to my original point.

> And now
> some people work on using BrandZ (if you know nothing about it, it's
> sort of like our technology used to do our linuxulator or freebsd32 on
> amd64; that's not accurate, but is good enough for the point I want to
> make) to provide a Solaris 10 container (think about it as a jail on
> steroides) with an Solaris X (X < 10) image, so that people can install
> a Solaris 10 host and run Solaris X in it (like our linuxulator in a
> jail, but not as flexible as our linuxulator, theirs can not run on the
> main system like ours can).

Right, having the linuxulator in the kernel is all but
unavoidable. But for old FreeBSD apps running on newer versions of
FreeBSD, we can do better, and a library-based approach is easier
to maintain and less prone to security problems.