Polprog's Am5x86 based retro UNIX build log

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I have recently acquired an Am5x86 computer, in a surprisingly good condition. This is an ongoing project, check this page often for updates!

The hardware

I began by connecting a front panel. The panel came from a different chassis and is slightly too wide, so I had to attach it with a couple of zip-ties. However, that makes it stick out from the PC front at an angle, allowing easy access when the computer sits at the floor - and thats where it is most of the time. It's not that bad, to be honest, and its way easier to access than it would be, if mounted vertically

There is a mains switch on the front panel because the computer uses an older style power supply. Those power supplies instead of relying on a PSON signal, like modern ATX supplies, run a 4 wire cable to a mains switch. The cable carries live and neutral both ways, and the switch keys in or out the power. The system powers on as soon as the switch is enabled.

Originally there was no graphics card in it. Since a PC will not boot with out a GPU, I had to find one. The mainboard only has PCI and ISA slots, and all the GPUs I had were AGP. Fortunately, I bought a PCI GPU hoping it would solve my issue...

However the GPU turned out to be faulty. It took me some time to repair it. I had to repair a broken trace leading to one of the EEPROM pins, and replace a contact in the EEPROM's socket. Then I replaced all the electrolytic capacitors on it, and that fixed it for good.

Having used up only one of the three PCI slots, I populated the remaining pair with two ethernet cards. I still have a bunch of ISA slots available, but I have nothing to install there. Yet.

Storage media

I have fitted the computer with two 3.5" floppy drives and a CD-ROM drive. The main HDD is a 512MB PQI DiskOnModule. Those little modules are essentialy IDE flash disks. I bought mine for an equivalent of $8. It came without a power cable, and the power connector was something I had no matching plug for. I have taken the flashdisk apart and soldered two wires directly on the PCB. While still apart, I have also soldered an SMD LED to an unused footprint on the PCB. Now it blinks whenever the disk is accessed.

I still have a free 5 inch bay in the tower, and I'm not sure what to install there. It will probably be housing something I dont have yet. I have two ISA SCSI cards that I can use for some device.

386BSD install attempt

At first I tried to install 386BSD 0.1. I transferred the boot image on the floppy disk and it booted into a minimal shell. Unfortunately the installer fails when creating the file system (although running newfs directly does work). Since the installer is a binary, and I don't feel like debugging a nearly 30 year old OS, there's not much I could do...

I've also discovered an easter egg... This shows up when there arent any hard disks detected by the OS

I tried to install it on a different hard disk, a 40 GB one, but it failed with "invalid seek" while formatting.

BSD/OS 4.2

Fortunately archive.org published many BSD/OS install media. I went with version 4.2. BSD/OS feels incredibly modern on the first impression. However, the bundled software age starts to show...

Currently its the operating system installed permanently on the 486. More information on running BSD/OS are on this page


While searching for floppy images online, its impossible to miss the plethora of DOS software and boot floppies. I've got original DOS 6.22 and Windows NT install media, a DOS 6.22 and 3.3 on a bootable floppy. See MS-DOS page for more.

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