This patch is for the model 50z and 70 to allow the 2.0a OS to run. The model 70 has no exceptions. The model 50z has 1- The 3c523 board running NON-dedicated only!!! It is recommended that the 3c523 not be run non-dedicated at this time. The patch is ran as follows, 50znded.exe is ran against the nondedicated OS ONLY!!!! syntax "50znded" follow instructions 50zutils.exe is ran against the "dedicated OS" and all the disk utilities ( compsurf install disked) syntax "50zutils" follow instructions NOTE:Once the patch is ran, the OS can only be used on the 50z or 70 and not on any other microchannel F/S !!!