set datafile missing "?"
set xrange [0:5]
set xtics ("ms" 0, "mod" 1, "al" 2, "ms:mod" 3, "ms:al" 4, "mod:al" 5)
#set yrange [-1:1]
set style data linespoints  
plot '@file@' using :1 title "new", '@file@' using :2 title "mode", '@file@' using :3 title "alea", 0 notitle