There was a Zenith MS-DOS 3.31+ that ran on the
Z-150/Z-151;
I can probably scare it up...
I've got a few sets of DOS 3.3+ for the Z-248 but not for the
Z-150/151.
It should work on the 150s. The 248 is an AT type machine (286 CPU,
built in hard drive,e tc) and the 150s are XT type machines (8088 CPU).
joe