Subject: Re: Post.Office + NetBSD
To: David Hopper <email@example.com>
From: Chris G Demetriou <Chris_G_Demetriou@ux2.sp.cs.cmu.edu>
Date: 11/07/1996 19:33:11
> Do you need the shadow tree? If so, how the devil could I find
> the requisite BSDI libs if the OS is commercial?
Congratulations, you've found the serious (and, in my opinion, fatal)
flaw in NetBSD's binary emulation strategy!
In other words, basically, "you can't."
It's a joke that NetBSD claims binary emulation capabilities for the
various commercial OSes that it does, because you cannot use those
emulation capabilities unless you're licensed for the OSes in
question. Thus, NetBSD's binary emulation of commercial OSes is
(1) for statically-linked binaries,
(2) by people who have licences for the
(commercially-licensed) libraries in question (i.e., most
likely are migrating to NetBSD from that OS, or just
playing around with NetBSD), or
(3) by software pirates, who don't care if they have to steal
the aforementioned libraries.
There are probably several solutions to this problem. One, which was
taken by BSDI for their SCO emulation, is to write and build libraries
which look and act sufficiently like the target OSes' libraries that
emulated binaries can't tell the difference. For commercial systems
which are claiming binary emulation capabilities, this is necessary;
they can't limit their capabilities' usefulness to the set of binaries
and people mentioned above.
I think it's inappropriate that NetBSD trumpets its commercial-system
binary emulation capabilities so loudly when it falls so far short of
actually providing useful and complete emulation for those systems.
Note, of course, that this only applies to binary compatibility with
commercial systems; more proper binary compatibility with free OSes is
possible, but only because they give away their libraries (and
e.g. shared loaders).