A personal note on the origins of the name "parfu" by Craig Steffen, sole developer of parfu through versions 0.4 and co-developer since.
The name "parfu" for this application was the second name we found, both times after extensive searching and googling and checking urban dictionaries to avoid unfortunate synonyms and find things that were fairly unique.
I think it's useful for the name to at least slightly suggest its lineage. Parfu is basically a parallel version of tar; it does exactly the same job. I wanted to hold onto the "ar" part of "tar", for "ARchive", since that's the relevant concept.
In its early conception in 2015, this software was called "Dart". My mental image was fifty people throwing darts at a single dart board. That's conceptually how the ranks in parfu (or dart) work. The ranks are all collecting data for the archive file, and blasting into the one file simultaneously in time, and the archive file fills up fast.
However, we later found out that not only does Google have a language called "dart", it has a published specification about it. So we decided that was a bad idea, as neat as the name is.
The word "Kung-Fu" originally approximately meant in Mandarin "excellence of self", being in your whole self the best you can possibly achieve. When characters in, say, early Bruce Lee films say things like "your kung-fu is strong", they don't mean that your martial arts are powerful, it meant that you have inner power that you're using effectively. In the DreamWorks short "Kung Fu Panda: Secrets Of The Furious Five", Po (the titular Panda) makes a very good explanation of the original core meaning of the word kung-fu. However, the martial arts meaning has taken hold as the meaning of that word in english. So much so that the people refer to "google-fu" as your ability to use google, or "script-fu" as your ability to write scripts effectively (both from the urban dictionary).
I picked up a slight variation of this as I was taking two semesters of Mandarin language in the fall of 2015 and spring of 2016. One of the conversations we memorized had someone taking a guest into their home office, where they notice a small dog under the desk. The host says the dog's name is "Laifu", which is a common name for a pet dog in China; it means "brings luck".
The key thing that makes parfu what it is its parallel nature. Dividing up the reading and the writing is why it works well.
So putting all of this together, the name "par-fu" means something like "parallel archive strength" or "the power of parallel archiving, or "parallel-archive-fu".
In all my google searching, I couldn't really find anything with that name. Wikipedia, google, and the urban dictionary all came up empty. Also, domain names were available, so information about the application can be found at parfu.net.
Finally, as far as I can tell, the three-letter file extension ".pfu" has never been used for anything significant. So possibly, .pfu files are unique in belonging to this application.
-- Craig Steffen, July 2017