Interestingly, 7z is also of Russian origin (Igor Pavlov), and a lot of data compression research comes from there too --- possibly a legacy started by Markov.
That, and the fact that our computers were really shitty. :) It also helped in development of very clever analytical and numerical integration techniques, e.g. Sobol sequences.
That's really interesting. When working under constrainst people get creative. I think it just happend so that most computers that I've worked on don't handle RAR by default so I never knew the background.
I believe this is a holdover from piracy the early 2000s, when file sizes needed to remain small (due to unreliable downloads or the need to fit on a particular piece of physical media) and RAR was a convenient format for generating compressed archives in multiple parts.
I recall it being the common go-to for file-sharing (piracy) uploads on Usenet. I'm not sure if it was because of repair-ability when you were missing some of the RARs, file-size limitation, resume-ability, low bandwidth, etc... Probably a combo of them all I guess; wasn't aware it was still used nor that it might be more common in RU.
I have always when encoutering RARs rolled my eyes and then tried to remember the names of tools to do extraction.