80386

   Also called the 386DX and the 386. A full 32-bit microprocessor introduced by Intel in October 1985 and used in many IBM and IBM-compatible computers. The 80386 has a 32-bit data word, can transfer information 32 bits at a time over the data bus, and can use 32 bits in addressing memory. It has the following modes:

   1) Real mode effectively limits performance to that of an 8086 microprocessor and can address 1MB of memory.

   Protected mode prevents an application from stopping the operating system because of an error, and it can address 4GB of memory.

   Virtual 8086 mode allows the operating system to divide the 80386 into several virtual 8086 microprocessors, all running with their own 1MB of space, and all running a separate program.

   2) Real mode effectively limits performance to that of an 8086 microprocessorandcan address 1MB of memory. Protected mode prevents an application from stopping the operating system be80486

   Also called the 486 or i486. A 32bit microprocessor introduced by Intel in April 1989. The 80486 adds several notable features to the 80386, including an onboard cache, a built-in floating-point processor, and a memory management unit (MMU), as well as advanced provisions for multiprocessing and a pipelined execution scheme.