Flash forward to today, and Windows and OS X have both figured this out. Windows 7 uses a similar solution to Solaris, installing both 32-bit and 64-bit versions of all libraries, and having a separate "x86" folder for all programs. OS X uses "universal binaries," which allows builds for multiple architectures to be packaged into the same binary. In either case, everything Just Works and it's great!
Off in Linux land, it's a distribution-by-distribution attempt at solutions for this problem. Some distributions have it figured out, others don't. The solutions chosen by various distributions aren't the same. On some of the more popular distributions there is no Just Works solution to running legacy 32-bit programs on a 64-bit install. Even if you are able to install a base set of 32-bit libraries, installing the many other dependencies of a 32-bit program on a 64-bit system can often be a rather challenging task.
So it was rather disappointing to read that an attempt to add OS X-like universal binary support to Linux, the so-called FatELF executable format, was discontinued today. FatELF offers something Linux desperately needs: a kernel-level solution to the 32/64-bit binary problem, the kind every distribution could automatically fall in line with. The infamous Ulrich Drepper's response to the suggestion of fat binaries for Linux was expectedly blunt:
Yes. It is a "solution" which adds costs in many, many places for a problem that doesn't exist. I don't see why people even spend a second thinking about this.Yes, Ulrich Drepper, the 32/64-bit binary support problem on Linux is totally and completely solved. It should be no problem to install a 32-bit version of any application on any Linux system today, right? Even if it's running a 64-bit distribution? Yes, that problem does not exist.
Maybe if we all pretend the problem doesn't exist it will go away.