In the early 1980s
Intel, the creator of
80286, was aware of that microprocessor's poor reputation. The company's own engineers believed that
Motorola 68000 was superior to their "ugly duckling".
Bill Gates called 80286 "brain dead", and important customer
IBM thought that its architecture was a flawed dead end. While the company expected that
Intel i432 would be its future architecture, i432 was very slow and many also believed unsuitable. Groups worked on various successors, including a completely new architecture ("P4") from i432 designer
Glen Myers that resembled
DEC VAX, and another ("P7") intended to combine Myers's work and i432 technology. Although many in the company believed that a 32-bit successor to 80286 was nonviable, Gene Hill and 80286 co-designer Robert Childs secretly worked on the "stepchild" project and persuaded others of its potential over Myers's plan, which people such as
John Crawford compared to the events at
Data General in
The Soul of a New Machine.
Binary compatibility with the
Intel 8086 architecture the recently introduced
IBM PC used was at first not seen as important, and many disliked the older CPUs'
segmented memory model. A greater priority was a 32-bit
flat memory model so 80386 can, like 68000, run
Unix well. 80386 development began in 1982 under the internal name of P3. Intel previously used
NMOS logic but 80386 was its first
CMOS product, consistent with the industry trend. The rapidly growing IBM PC
installed base made supporting its software library more important, and Intel salespeople told customers that their 286 software would run on 386. The 386 designers thus supported both flat and segmented memory models, what Crawford described as "the best of both worlds".
Pat Gelsinger led the port of
Amdahl UTS to the CPU to confirm Unix's viability. The limited
die size made difficult incorporating, for marketing purposes, a
CPU cache twice as large as the
68020's. The team's Jim Slager later described both CPUs' caches as useless, but he and his colleagues succeeded. The
tape-out of the 80386 development was finalized in July 1985. The 80386 was introduced as pre-production samples for software development
workstations in October 1985. Intel had exited the
DRAM market to focus on microprocessors, so the former "stepchild" was vital to its future; the company moved memory engineers to the 80386 project, improving the
die shrink. The forthcoming product persuaded customers that the 80286 was not a dead end, increasing the latter's sales. 80386 manufacturing in volume began in June 1986, along with the first plug-in device that allowed existing 80286-based computers to be upgraded to the 386, the Translator 386 by
American Computer and Peripheral. The 80386 being
sole sourced made the CPU very expensive, but it was very successful. Hill recalled representing the design team at a
PC Magazine awards ceremony: Although the multiple segment models were rarely used their existence may have benefited Intel, because the complexity slowed other companies' ability to
second source the CPU.
Mainboards for 80386-based computer systems were cumbersome and expensive at first, but manufacturing was justified upon the 80386's mainstream adoption. The first
personal computer to make use of the 80386 was the
Deskpro 386, designed and manufactured by
Compaq; this marked the first time a fundamental component in the
IBM PC compatible de facto standard was updated by a company other than
IBM. The first versions of the 386 have 275,000 transistors. The 25 MHz 386 version is capable of 7 MIPS. A 33 MHz 80386 was reportedly measured to operate at about 11.4 and 11.5 MIPS. At that same speed, it has the performance of 8
VAX MIPS. These processors run about 4.4 clocks per instruction. After AMD and
Chips and Technologies released 386-compatible CPUs, Intel in 1992 lowered the price of its 25-MHz
80486SX processor to less than that of the 33-MHz 80386. An industry analyst said that Intel wanted customers to move to the competition-free 486. The strategy was very successful; by 1993 many computer companies had discontinued 80386 products or planned to do so later that year. Customers who found that
Windows 3.1 ran slowly with 386 were willing to pay $200–300 more for 486;
Dell reported that 80486-based computers were 70% of sales. In May 2006, Intel announced that i386 production would stop at the end of September 2007. Although it had long been obsolete as a
personal computer CPU, Intel and others had continued making the chip for
embedded systems. Such systems using an i386 or one of many derivatives are common in
aerospace technology and electronic musical instruments, among others. Some mobile phones also used (later fully static
CMOS variants of) the i386 processor, such as the
BlackBerry 950 and
Nokia 9000 Communicator.
Linux continued to support i386 processors until December 11, 2012, when the kernel cut 386-specific instructions in version 3.8. == Architecture ==