AbstractThe paper shows the history of developing the PARS family of commercial machine translation systems for Russian, Ukrainian, English, and German, developed by Lingvistica '98 Inc. It discusses three aspects: retrospective, technological, and linguistic The main focus is on dictionary updating as one of the most important components of a commercial MT product. Each of the PARS systems features a unique tagging option, which makes it possible for the user to have grammatical data assigned automatically to Russian and Ukrainian words entered into the dictionaries. Besides, PARS dictionary officers make use of the batch-mode tagging technology, due to which PARS features very large bidirectional Russian-English general and specialist dictionaries of more than 1,000,000 translations for each translation direction, as well as large bidirectional Ukrainian-English professional dictionaries. The PARS family was designed in the mid 1980s, and it has been and is now in commercial use since 1989 all over the world.