Is the peripheral mapped I/O different from what is known as port-mapped I/O or simply known as I/O mapped I/O? I don't see the usage of the term "peripheral mapped I/O" around much. Was it only relevant to 8085 microprocessor?
Peripheral-mapped IO is the same as the port-mapped one. It is using a distinct address space, and the addresses are known as port numbers. The other one is the memory mapped IO, which is using the same address space as the main memory, such that it has some specific control registers at specific memory addresses instead of "ports".