386
386 tech specs
- Company: Intel
- Type: Microprocessor
- Address width: 32 bits (can access up to 4 GB of RAM or ROM)
The 386 (short for 80386) was a 32-bit microprocessor released by Intel in 1986.
Its 286 predecessor rather questionably divided memory up into separate 64 KB chunks known as segments. In contrast, the rival 68000 chip had a flat memory model, able to address up to 16 MB contiguously. This made the 68000 chip far superior for running Unix.
The 386 was therefore designed to work both ways, able to segment memory into 64 KB chunks if needed, but also able to use a flat memory model that encouraged Unix ports, allowing it to compete with the 68000. Its designers achieved this by allowing each segment to be as large as the full 4 GB, and therefore only having one single segment,[1] for those who didn't want segments in the first place... which was seemingly everyone except IBM.
This plan worked, at least on a technical level. On the one hand, like its predecessors, the 386 was only really used in beige box IBM PC clones. On the other hand, enterprising programmers soon wrote free Unix clones for those PCs. This allowed them to be repurposed as a (relatively) poor person's home server, replacing Windows with Linux, NetBSD, or FreeBSD.
Admittedly, companies making serious workstations running proprietary Unix variants still favoured the 68000, as did everyone else not cloning the IBM PC. But computer hobbyists sure appreciated the 386 for helping bring free Unix clones to the masses.
Quotes
Well we thought that was a key market segment for the 386. It was not a market segment where the 286 was doing well at all; it was a market segment where the 68000 was cleaning up, principally because the 286 was not viewed as a machine that ran Unix well, and the 68000 was viewed as a natural Unix machine. So when we were working on the 386 definition, we wanted it to have as one of its attributes being able to run Unix well. So that's one of the things that influenced us, in terms of wanting to have a way to run the 386 as a flat 32-bit machine, and that's one of the things that led to all the angst in the definition process about compatibility versus a flat 32-bit machine, and how they would coexist.
— Jill Leukhardt, 2008[1]
References
- "Intel 386 Microprocessor Design and Development Oral History Panel" Jim Jarrett, Dec 2008
Intel: 386
Microprocessors: 386 | 68000 | HD6303X | μPD780 | μPD8080 | μPD70216
