Mach386: MACH and BERKELEY UNIX for i386

I’ve been looking for this, since I first found out about it a few years ago. It’s a port of 4.3BSD Tahoe to the i386, utilizing the Mach kernel. This is the biggest gap of the era, which is bringing mini-computer BSD to an affordable platform, the AT386.

Sadly like many others after Mach386, it did not find widespread commercial success and MtXinu wound down operations of the product, and eventually the company itself. It’s a shame too that both Mt Xinu & BSDi eventually exited the BSD market, while the open 386 alternatives flourished and grew.

One thing is for sure, it wasn’t cheap! At least on the perpetually starving college student budget the base license was $995! And that included no source code at all. Although the Mach 3.0 Add-on does include source code, however because of the then new AT&T USL vs. BSDI/UCB lawsuit CMU got cold feet over it’s BSDSS/BNR2SS for Mach 3.0 and pulled it, leaving you with a micro kernel with no personality. Although years later the rights would flow from AT&T to Novel who then let Caldera acquire them, and then give the infamous 32v giveaway (pdf) essentially setting BSD free. Although I was one of the people who shelled out the $100 for the oldSCO SYSIII license back in the day.

Mach386 lived from around 1991 until 1993. Needless to say the Juggernaut called Linux appeared at the right time and the right place, when all of the BSD’s had faltered because of that lawsuit. Sometimes in life, timing is absolutely everything.

Sadly by the time I could afford expensive OS’s it was 1999 and I’d bought OS X Server 1.0, with all it’s 4.4BSD + Mach 2.5 fun.

Anyways fast forward a few decades and I have been looking for a mythical 4.3BSD on i386 for far too long, and I came across a post on betaarchive mentioning, and all of Scott’s adventures with Mach386. So I was able to contact him, and get a copy of Mach386!


Well the disk set is from 1992, and going back to that era means you are going be locked into the old disk geometry where an IDE disk under 500MB is the best way to go. The floppy controller is programmed in a weird way that the only thing I could get it working with was VMWare. It wasn’t so bad going through the disks, and I quickly had a system up and running. Once the install is done it’ll run under QEMU for instance just fine.

Mach386 on Qemu

Currently there is no ‘modern’ ish networking support, aka no NE2000. So I’ve been using serial terminals to use uuencode/uudecode to get files in & out of the VM.

So what’s in the box? Well I didn’t install the X11 stuff as I’m just not in the mood to fight it, but it’s a 4.3BSD system! Sadly adventure/zork is absent, however rogue and all the other BSD type fun is there. gcc version 1.37.1 & GNU assembler version 1.36 among others are also includes, although without any diff’s or source. Although the networking headers & tools are on separate disks, there is no nonsensical link kit type thing like Xenix, meaning that TCP/IP is fully integrated to the kernel. While there is SLIP support apparently I haven’t messed with it at all yet.

What is really interesting is the other disk set, MtXinu-Mach386-M3921131020-Mach_3.0+DUI.7z which is that Mach 3.0 kernel version MK78 which I believe is the first widespread & public release of Mach 3.0.

Being that this a Mach based system it builds the 3.0 kernel with ease. It even includes a 4.3BSD (sadly binary only) ported kernel to the 3.0 Mach which you can run. It’s defiantly not as fast as the default kernel, but seems to work well enough.

The kernel in question is what they term Mach 2.6 which is the 2.5 plus lots of enhancements. Among others is a different disk layout/partitioning scheme so you can dualboot. Although in the era of cheap VMs it’s kind of pointless.

So it may not look like much, but it’s a really fun thing to play around with. At the same time 386BSD had been pushed out into the world, and Linux was also a thing. It’s not surprising that Mt Xinu & BSDi would eventually fail in the marketplace, and Linux would go on to decimate the UNIX landscape. But it’s cool to run a direct VAX based OS on the PC.

2 thoughts on “Mach386: MACH and BERKELEY UNIX for i386

  1. “The floppy controller is programmed in a weird way that the only thing I could get it working with was VMWare.”

    Did you try it in 86Box/PCem? I curious if it would work there. Particularly since it emulates far more old hardware (NE1000/EtherLink II/ISA SCSI cards/etc.).

    • I tried the latest build, and it ‘sort of works’. It’ll lock up on reboots when trying to load the kernel. I had to kill 86box and re-launch to get past certain booting stages.

      I used the following:

      AMI i386DX/33 with 80387 & 12MB of RAM
      3.5″ 1.44 300/360 RPM
      IDE disk with 1015c 16h 63s

      I should add that after the fact it doesn’t install properly. Files went missing during the install, although the installer didn’t complain. So 86box current build just doesn’t work well enough.

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