How to find VERSION Unix OS

Mon May 27 20:41:34 AEST 1991

>Convex :
>
>CONVEX> adb -k /vmunix /dev/mem
>sdr[0] = 00200010  sdr[1] = 00000000  sdr[2] = 00000000  sdr[3] = 00200210
>sdr[4] = 00000000  sdr[5] = 00000000  sdr[6] = 00000000  sdr[7] = 00000000
>Convex Debugger ($Date: 88/09/21 15:51:31 $)
>Use ')help' for help.
>(adb) version/s
>_version:       ConvexOS -- Version 9.0.7.0.4 Tue May 14 10:25:57 CDT 1991
>(adb)
>

Why not use vers ?