They are typically associated with mainframe and minicomputer operating systems. Nanocomputer refers to a computer smaller than the microcomputer, which is smaller than the minicomputer. Several other HP divisions created similar minicomputer or microprocessor stack machines. The microprocessor recognised the DEC PDP-8 minicomputer instruction set. Bitboards may not be effective on earlier 8- and 16-bit minicomputer and microprocessor architectures. SCAMP emulated an IBM 1130 minicomputer in order to run APL/1130. SCAMP emulated an IBM 1130 minicomputer in order to run APL1130. Today only a few proprietary minicomputer architectures survive. An IMP was a ruggedized Honeywell DDP-516 minicomputer with special-purpose interfaces and software. The IBM Series/1 minicomputer also use big-endian byte order. The 1980s saw the minicomputer age plateau as PCs were introduced. Most minicomputer systems from DEC used this convention. It was greatly influenced by the HP 3000 minicomputer. Electronic mail use was initially restricted to a single minicomputer. The Data General Nova minicomputer had 16 special memory locations at addresses 16 through 31.