I got a laptop running Ubuntu 14.04 and I want to install some abandonware in virtual machines with VirtualBox and I chose to begin with AT&T UNIX 4 Version 2.1.

I allocated for this machine 512 Mb of RAM,16 Gb storage, 32 Mb video memory, 1 CPU with 1.3 GHz and the boot order is CD/DVD;Floppy;Hard Disk. It says to press F12 to start the setup and afterwards it shows me VirtualBox temporary boot device selection, with four options:

1) Primary Master;

I tried all of them and and everytime it gives me the error:
"FATAL Could not read from the boot medium.System halted."

And my CD_ROM image is allright, I downloaded it from here and extracted it, then made an ISO file with Brasero,the file occupies now 44.3 Mb.
What should I do? What did I do wrong?


Unix System V doesn't support large hard disk sizes. I think 505 MB is the maximum that it can handle. I got the same "PANIC: HD CONTROLLER: COMMAND ABORTED" error when using virtualbox, until I realized that it had automatically made the hard disk size 1 GB.

  • I could have sworn that system came out before the advent of IDE hard disks. – psusi Mar 15 '18 at 17:47

What should I do? What did I do wrong?

You created a unbootable iso. You should have read the README file which says:

Boot from base1.img and follow the on-screen instructions to install the base system.

That means you need to add a floppy controller to your VM and use the file named base1.img (actually "Base 01 (2.1a).img") as virtual medium instead of creating a iso.

To be honest, that might not be the end of your issues as, using the same files and VirtualBox, I never went further than either a panic at boot time :


or an abort with this message:

Incorrect UNIX System "Base System Package" Floppy Disk 1

This disk is not appropriate for
machines exclusively equipped with SCSI peripherals.

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