PDP-11, a popular 16-bit minicomputer during the 1970s The
MIT Whirlwind ( 1951) was quite possibly the first-ever 16-bit computer. It had an unusual word size for the era; most systems used
six-bit character code and used a
word length of some multiple of 6-bits. This changed with the effort to introduce
ASCII, which used a 7-bit code and naturally led to the use of an 8-bit multiple which could store a single ASCII character or two
binary-coded decimal digits. The 16-bit word length thus became more common in the 1960s, especially on minicomputer systems. Early 16-bit computers ( 1965–70) include the
IBM 1130, the
HP 2100, the
Data General Nova, and the
DEC PDP-11. Early
16-bit microprocessors, often modeled on one of the mini platforms, began to appear in the 1970s. Examples ( 1973–76) include the five-chip
National Semiconductor IMP-16 (1973), the two-chip
NEC μCOM-16 (1974), A similar analysis applies to Intel's
80286 CPU replacement, called the
386SX, which is a 32-bit processor with 32-bit
ALU and internal 32-bit data paths with a 16-bit external bus and 24-bit addressing of the processor it replaced. ==16-bit application==