>This is the dumbest research I've seen in 2015. There was actually no computation involved -- they just wanted to write a long string to disk. They concluded that adding the superfluous step of concatenating strings in memory, then writing to disk, was slower. Well duh! That's not what memory is for!
Agreed with you on the uselessness of their research, but that is most definitely one important and common use of memory: buffer caches used by the operating system.
Effectively, they unintentionally tested the speed of the OS to concatenate strings vs Java or Python. The researchers are wrong right out of the gate: they say "Heavy Disk Usage" in their research headline, but at no point did they actually test disk performance, everything they did is being handled by the OS buffer cache.
All the researchers have shown is that string concatenation operations in Java and Python are atrociously slow. The java example used the naive form a=a+b; to concatenate strings, which is one of the slowest ways to do it in Java if you are doing repeated concatenations to a string.
If, in their tests, they had also done a string concatenation in C by allocating a buffer and appending to it using a pointer (not strcat) the speed difference doing that vs. 1 million write calls would have been negligible.
Also, if they sync'd after each of a million 1-byte writes to test how slow "Heavy Disk Usage" is compared to a single write of a million bytes, they wouldn't have bothered finishing this paper at all because it's so damn obvious that memory is faster.