Intel and compatable CPU's Programming Information
Intel 80386<Processor> (Commonly abbreviated to "386", trademark "Intel386") The successor to the Intel 80286 microprocessor It was the first Intel processor with 32-bit data and address busses called IA-32. It can address four gigabytes (2^32 bytes) of memory; however, 16 megabytes is a typical maximum in IBM PCs. The 386 allows multiple application programs to run at the same time (when running under 386-specific operating systems) using " protected mode".
The 80386 initially shipped at 16 MHz in October 1985, making it faster than any Intel version of the 80286. Note, some others had overclocked 286 Processers up to 20Mhz.
It did not require special EMS memory boards to expand
MS-DOS memory limits like the 80286 did. With the 386, the EMS standard can be
simulated in normal extended memory, and many DOS add-ons
provide this "Expanded Memory Manager" feature.
This was the first X86 processor that could eliminate the 64K memory segmentation issued that programmers had to deal with
Some of the first operating systems to support the 386 processor was Bill Jolitz's 386BSD, BSDI's BSD386, Bill evans's Minix 386, and Linux. Then Microsoft Windows 3.1 .
Intel 80386 Reference Programmer's Manual