+ /* fsync can be a significant performance hit. Often it doesn't
+ suffice to make the file-save operation survive a crash. For
+ batch scripts, which are typically part of larger shell commands
+ that don't fsync other files, its effect on performance can be
+ significant so its utility is particularly questionable.
+ Hence, for now by default fsync is used only when interactive.
+
+ For more on why fsync often fails to work on today's hardware, see:
+ Zheng M et al. Understanding the robustness of SSDs under power fault.
+ 11th USENIX Conf. on File and Storage Technologies, 2013 (FAST '13), 271-84
+ http://www.usenix.org/system/files/conference/fast13/fast13-final80.pdf
+
+ For more on why fsync does not suffice even if it works properly, see:
+ Roche X. Necessary step(s) to synchronize filename operations on disk.
+ Austin Group Defect 672, 2013-03-19
+ http://austingroupbugs.net/view.php?id=672 */