History and versions
PhysTechSoft was formed in 1991 in Moscow, Russia by graduates and members of Moscow Institute of Physics and Technology, informally known as PhysTech. At the end of 1993, PhysTechSoft released the first commercially available PTS-DOS as PTS-DOS v6.4.The version numbering followed MS-DOS releases numbers, as Microsoft released MS-DOS 6.2 in November 1993.
In 1995, some programmers left PhysTechSoft and founded Paragon Technology Systems. They took source code with them and released their own version named PTS/DOS 6.51CD as well as S/DOS 1.0 ("Source DOS"), a stripped down open-source version. According to official PhysTechSoft announcements, these programmers violated both copyright laws and Russian military laws, as PTS-DOS was developed in close relationship with Russia's military and thus may be subject to military secrets law.
PhysTechSoft continued development on their own and released PTS-DOS v6.6 somewhere between and presented PTS-DOS v6.65 at the CeBIT exhibition in 1997. The next version from PhysTechSoft, formally PTS/DOS Extended Version 6.70 was labeled PTS-DOS 2000 and is still being distributed as a last 16-bit PTS-DOS system.
Paragon continued their PTS-DOS line and released Paragon DOS Pro 2000 (also known and labeled in some places as PTS/DOS Pro 2000). According to Paragon, this was the last version and all development since then ceased. Moreover, this release contained bundled source code of older PTS-DOS v6.51.
Later, PhysTechSoft continued developing PTS-DOS and finally released PTS-DOS 32, formally known as PTS-DOS v7.0, which added support for the FAT32 file system then PTS-DOS 2000 that contains all the programs necessary for working on the Internet.
The PTS-DOS 2000 Internet software package includes: graphical web browser, e-mail client, ftp client, telnet, Internet connection tool (dial-up).
PTS-DOS is certified by the Russian Ministry of Defense.