Q. 1) what is AS/400?A. Application System/400. IBM's mid-range processor. Q. 2) diff. between OS/390 and Z/Os? The latest name in a long succession for the high end IBM mainframe operating system that began life as OS/360 and reprised that name as OS/390 replaced MVS. OS/390 was replaced by z/OS along with the introduction of eserver, including a complete line of mainframes called zSeries 900, most notable for its 64-bit addressing and IRD. z/OS also runs on System/390 G5, G6 and Multiprise 3000 systems. Advantages of OS/390: The advantages of OS/390 is against MVS and not against Z/OS since Z/OS is an extended version of OS/390.
1. Attractive pricing at the lower levels.
2. Encourage developers to write applications in a shorter period of time.
3. Reduced IBM's testing costs dramatically because there was no longer a need to test every combination of supported releases of what were now components instead of separate system software products.
4. Provided users with common services across all the major IBM platforms. [/quote]