I was reading this stuff from a website :
Multiprocess operating systems (for example Linux®) can switch between application
programs running in 32-bit computation mode using a 32-bit ABI and programs running
in 64-bit computation mode using the 64-bit ABI. In order to support both the 32-
and 64-bit computation mode application programs, the operating system itself must
execute in 64-bit computation mode and must have the ability to load multiple
executable files.

Single-process operating systems such as VxWorks can only execute application programs
using a single ABI.

What would single/multi process mean in this context.
The architecture supports both 64 & 32 bit addressing and we have a biarch toolchain
that makes things possible.

Waiting for your comments.