Warner Losh

Venix/86 was the first commercially available Unix for the IBM PC. PC/IX was the first one that IBM supported, but VentureCom created released this port about the time PC/IX was announced. They ported it to a number of the 'near compatible' systems as well, so for many people the first Unix available on those early 8086/8088 machines was Venix. This included the DEC Rainbow 100B with Venix/86R.

A companion project to recreate the sources for Venix/86 from 7th edition tapes now available was hampered by the slow speed of the DEC Rainbow, so I wrote the emulator to seed that along.

This talk will be about the emulator's structure, system call interface and portability to other ancient 8088/8086 Unixes. It will also discuss how many of the early ports coped with lack of a MMU in clever ways. It will touch on the path here, and then focus on the current implementation.

The author had a DEC Rainbow which was supported with Venix/86R. By the time the author was employed post college, copies of it had become impossible to find.

Recently, A copy surfaced and I started working with it. A number of interesting challenges for creating this port will be discussed. I took the hard path to decompile parts of libc to discover the system call interface, and went through a few preliminary implementations of Venix/86 emulation before arriving at what we have today. After the initial decompile, documentation surfaced, other incomplete copies were found along with some source, all of which confirmed most of the details that had been guessed.

This has been a labor of love for me, using 4 different x86 emulators, a number of deep searches online to find as much info as I can, disassembly, etc. I'll touch on some of these aspects as well. It's currently running using vm86 on a FreeBSD/i386 bhyve instance hosted on a FreeBSD/amd64 machine nicely... A port to qemu user-* might be possible too.

This goes hand in hand with another project: recreate the sources that can create a Venix kernel using the now-available 7th Edition sources, which may be a future submission.

The early history of Unix is much richer than is usually presented. There are many hidden gems that are little known and quite interesting to learn about. The dates of many of the "firsts" for Unix accomplishments is much earlier than people think. This well-researched talk explores those gems, firsts and shares many artifacts from the early days of Unix. Many of these artifacts have just come to light in recent years, and change how we view the early history of Unix. Even the oldest of grey beards will learn things they didn't know about Unix from this talk.

Most histories of Unix follow the same old boring plan: talk about Multics, Ken scrounging the pdp-7, moving to the pdp-11, rewriting in C and then the explosion that happened with V6 and V7 before jumping into the Unix wars between AT&T and BSD followed by something about Linux (either pro or con depending on the speaker's politics). We've all seen it, and many can predict which "classic" pictures will be used, the points that will be made, and the arcs drawn.

This talk is nothing like that. It brings all the early years of Unix to life in a unique way. The early years of Unix were surprising rich. The author will use original sources to take you on a tour of many of the firsts in Unix and explore the community ties key to Unix's early success. Many of today's fads, like microkernels, hypervisors, multiprocessing and user mode execution actually happened early on in Unix's history, long they were today's fads. "What's old is new again" has never been so apt. You'll be surprised to learn how early each of these things happened. Come see the secret history of Unix as it played out both in obscure business units of AT&T and in the world wide users groups who banded together to support each other when AT&T wouldn't. You'll see footage of early machines as well as the first real Unix application: space travel (newly rediscovered and restored by the TUHS group). See first hand the machines, programs, newsletters and documentation that together weave a rich tale of innovation, community and working within constraints. Learn how today's open source movement owes a debt to these early communities and how they paved the way for Unix to become the open and ubiquitous system it is today and helped sow the seeds for the communities of today.