References

OS/2 had true multi-tasking. As a demonstration, ten 1 million line files were each put on display to screen in ten separate windows. On Windows 3.1, only one at a time had display activity. On OS/2, all ten displays moved uninterrupted simultaneously. IBM LAN Manager also had better measurable performance, being based on an OS/2 server. This was in the early 1990's.[1]

  1. ↑ I was an OS/2 specialist and IBM LAN Manager Network Administrator with LA DWP, working there from 1990 to 2015.
source: http://simple.wikipedia.org/wiki/OS/2