Now `startx' behaves in a different way. Ran /usr/bin/startx /usr/bin/twm -- :1 It did create such a session. Was unable to figure on which virtual console it got. Clearly not one reachable with Alt-Fn key presses. Then ran /usr/bin/startx /usr/bin/twm -- :1 vt8 It did display the usual color of twm. But then the system ceased responding to any user actions (key presses, pointer movement). However, did switch hard disk LED on sometimes. Had to cycle power.