I know that my machine hardware name is i686 and processor type is i686 due to my Linux output. But I have no idea why they are the same. I want to know what's the difference between machine hardware name and processor type.
what's the difference between machine hardware name and processor type
linux kernel
This is explained more clearly in info uname:`-m'`--machine'     Print the machine hardware name (sometimes called the hardware     class or hardware type).`-p'`--processor'     Print the processor type (sometimes called the instruction set     architecture or ISA).  Print `unknown' if the kernel does not make     this information easily available, as is the case with Linux     kernels.So, the hardware name is the CPU architecture, while the processor type is the name of the instruction set used. To quote from wikipedia:Instruction set architecture is distinguished from the microarchitecture, which is the set of processor design techniques used to implement the instruction set. Computers with different microarchitectures can share a common instruction set. For example, the Intel Pentium and the AMD Athlon implement nearly identical versions of the x86 instruction set, but have radically different internal designs.