Linux Kernel supports 32-bit and 64-bit processor architectures and it supports almost all modern popular processor architectures such as:
ARM ( used in almost types of applications)
X86 ( Multimedia and industrial applications)
MIPS ( networking applications such as routers and hotspots)
PPC/PowerPC ( hard real-time and deadline constrained applications)
SH ( Multimedia applications)
In order to run Linux on a target embedded processor, a minimum of 8MB of RAM is required, however a real practical application requires at least 32MB RAM, but he actual requirement of the RAM memory depends on the embedded application size actually.
Toolchain is a set of programming tools (i.e. GCC compiler, C libraries, and GNU debugger,)that is used to perform a complex software development task or to create a software product, which is typically another computer program or a set of related programs....
The computer program that is responsible for booting the embedded hardware the first time we power it up.
It is a software or operating system kernel that manages resources of embedded processors optimally and efficiently.