Re: universal binaries

[Markus Hitter]

Am 17.09.2007 um 03:54 schrieb Frederico Muñoz:

> while adding stuff to
> the MAB's wouldn't bother the "official" tools for now, latter they
> could be rendered useless by conflicting definitions.

This is a risk you always have with proprietary OSs. Mac OS X is  
proprietary in this regard.


> > > (I'm not even considering different libc)
> >
> > Libraries use the same mechanism, so your libc has to contain a
> > cputype/architecturetype/platformtype matching your actual hardware.
>
> If I understand this correctly this is how GNUstep's non-flatened app
> structure work, and has full support of the runtime (especially since
> since it uses discrete binaries it dispenses any kind of special exec
> cooperation).

Nope. Libraries are FAT binaries in a single file, just like  
executables. Once the runtime-linker gets asked to load a library, it  
opens the file, looks at the header (if present), sets the offset  
according to the current architecture and works from there.


> For me the
> only allure this kind of MAB's have is e.g. having the same Emacs.app
> running on both OSX and, say, ix86 GNUstep. But again, this is
> simplistic and probably not worth the effort in a purely practical
> perspective. From a show case perspective,it would perhaps impress
> someone though.

Users stop having questions about what architecture to choose and  
distributions melt down to a single disk for all type of computers.

Sun probably doesn't use it because Apple has a patent on this stuff  
and didn't open source it until a few years ago.

The waste of disk space isn't that hard to bear with as applications  
come with a lot more graphics and localisations than executables  
these days. Additionally, you can strip unused architectures at any  
time.

The best thing is, you make mixed environments more simple, like 32- 
bit and 64-bit executables on the same platform, running side by  
side. The kernel runs whatever the developer provides and fits  
demands best.


Markus

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Dipl. Ing. Markus Hitter
http://www.jump-ing.de/