16-bit application

A 16 bit application is any software written for MS-DOS or early versions of Microsoft Windows which originally ran on the 16-bit Intel 8088 and Intel 80286 microprocessors. Such applications used a 20-bit segment-offset address representation to extend the range of addressable memory locations beyond what was possible using only 16-bit addresses. Programs containing more than <math>2^{16}<math> bytes (64 kilobytes) of instructions and data therefore required special routines to switch between their 64-kilobyte segments, increasing the complexity of programming 16-bit applications.

In computer science, 16-bit is an adjective used to describe integers that are at most 16 bits (2 octets) wide, or to describe CPU architectures based on registers, address buses, or data buses of that size.

The term "16-bit" can be used to describe the size of any of the following:

• A data unit.
  • A 4-bit unit (a hexadecimal digit) is called a nibble or nybble.
  • An 8-bit unit is called an octet (or a byte).
• A CPU's registers used to hold memory addresses and other data, as well as the ALU that operates on those registers.
  • Data units of that size are called words.
  • A 16-bit CPU can process 16 bits at a time.
• Memory addresses.
• Data transferred on each read or write of the memory.

See also

• Win32s
• 32-bit application