Citrix Multiuser is a customized version of Microsoft OS/2 1.21 that
turns it in to a real multi-user operating system. With Citrix
Multiuser, users can connect and simultaneously run character cell
based applications from remote serial terminals. To prevent users
from interfering with each other, it adds security permissions to
devices and files. It can use multi-port serial port boards like the
Digiboard, or any serial device that has OS/2 1.21 drivers.
based application or DOS executables, and programs can not use
graphics modes. It also does not have support for networking.
separation, which was an almost instant fatal blow as Citrix was
licensing OS/2 code through Microsoft.
making MS-DOS multi-user until eventually they released a Windows NT
based version.