I assume I don’t have to explain the difference between big-endian and little-endian systems to the average OSNews reader, and while most systems are either dual-endian or (most likely) little-endian, it’s still good practice to make sure your code works on both. If you don’t have a big-endian system, though, how do you do that? When programming, it is still important to write code that runs correctly on systems with either byte order (see for example The byte order fallacy ). But without access to a big-endian machine, how does one test it? QEMU provides a convenient solution. With its user mode emulation we can easily run a binary on an emulated big-endian system, and we can use GCC to cross-compile to that system. ↫ Hans Wennborg If you want to make sure your code isn’t arbitrarily restricted to little-endian, running a few tests this way is worth it.