MNOS (operating system)

MNOS (meaning "MobilNaya Operatsionnaya Sistema" (МобильНая Операционная Система, МНОС), or "Portable Operating System") was a Unix-like operating system developed in the Soviet Union.
Overview.
The system was derived from Version 6 Unix and consequently heavily modified to incorporate many features of BSD Unix. From 1983 until 1986 it enjoyed significant popularity in the USSR and other Eastern Bloc countries, due to its light weight and better performance than that of Version 7 Unix (and later BSD Unix-based) alternatives.
Its development was initiated in the IPK Minavtoproma in Moscow in 1981, and development continued in cooperation from other institutes, including Kurchatov Institute. MNOS and its alternative,
DEMOS version 1.x, were gradually merged from 1986 until 1990 resulting in the joint OS, DEMOS version 2.x.
MNOS became the first completely bilingual version of Unix, and used the proprietary 8-bit Cyrillic character set, U-code, which was later dropped in favor of KOI-8 in the process of merging with DEMOS.
The origin of the version qualifier "RL" is "Rabochaya Loshadka" (The working horsy)