[Discuss] RHEL on intel/Xeon, vs. RHEL on Mainframe "Z Linux"

[jim at gasek.net (Jim Gasek)]

BLU Discuss folks:

I have an application that I administer on RHEL 5.5.

I will be moving to 6.x, hopefully soon. 

It has been suggested that I consider moving it to the
mainframe, via RHEL for mainframe:

http://www.redhat.com/products/enterprise-linux/for-ibm-system-z/

What are the considerations for determining if my app will run
seamlessly on the mainframe RHEL?

"Porting" considerations?   Binary compatibility?
Libraries, compilers, ......

Perhaps there are additional "utilities" to take advantage of 
advanced features of the mainframe acrhitecture?

I know that in Intel architecture, there are certain "OpCodes",
or "functions of the chip", which are "taken advantage of",
as they become available, in more modern chips.   A compilation
of code would be tweaked to squeeze out maximum performance of
functions available on that chip/architecture.

Thanks in advance for your expertise.

Thanks,
Jim Gasek