32-bit machine:Typically, a 32-bit CPU means that the cup can compute 32 bits at a time. 64-bit machine:Typically, a 64-bit CPU means that the CPU can compute 64 bits at a time.
32-bit operating system:made for 32-bit machines. Refers to the operating system's word length is 32-bit, but also indirectly affect the address bus, therefore, the maximum address space is naturally 2 of 32 square, 4G. Note: The 32-bit operating system can only be installed on a 32-bit machine.
64-bit operating system:made for 64-bit machines. Refers to the operating system's word length is 64-bit, but also indirectly affect the address is idle, so the maximum addressable space is 2 of 64 square, 128G. Note: The 64-bit operating system can be installed on a 32-bit machine and can be installed on a 64-bit machine. But if the 32-bit efficiency will be much reduced.
these four concepts are different. Be sure to pay attention.
finally say why 64G compatibility is not good? Because the input-output is not worth, our usual 4G memory is not used up, so the operating system supporting 4G memory is enough for many users. 128G memory addressing space is generally used for enterprises and servers. Therefore, businessmen feel that the output of the 64G machine input drive is not worth it, so there will be a lot of incompatibilities for developers.
32-bit machine 64-bit machine 32-bit operating system 64-bit operating system
