Mainframe -OS/390 and ZO/s difference

This question asked for many mainframe programmers. They are unable to tell correct answer. For your benefit I am giving the basic difference.

OS/390:

This architecture runs under 32 BIT address space

Z/OS:

This architecture runs under 64-BIT address space.

Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.