PetrOS® Operating System

PetrOS® is a compact operating system which supports a very limited subset of the Win32 API.

It was originally developed by Trumpet Software International Pty Ltd, but has recently been acquired by Tattam Software Enterprises Pty Ltd.

The currently released version is 1.01, and is available for sale here

If you would like to try the demo version, a zip file containing the installation files is available here, and a README file to get you going. For ease of setup, a self extracting EXE of the zip file is also available here.

You will need a DOS bootable system to get it working as the installer runs from a DOS prompt, and also reset the date to 2001 as the this particular demo expired on 1/1/2002.

Please ignore any historic information about registration and support from the old site.

SHA1 checksums for the download files. 

63b2a75062b0a539d56f93e478a843f4bf7b3cca  PETROS-DEMO-1.01.EXE



ClassiOS - An Object Pascal Operating System

Tattam Software is redeveloping the PetrOS® IA32 (x86) OS project.  

This operating system is built entirely with the Delphi Compiler - even the boot loader!!  This was achieved by replacing the System.dcu and related units by a custom unit which can run in Ring 0 of the x86 CPU.


This is the commercial version of the free DOS TCP/IP stack (Peter Tattam's NTCPDRV) found at public FTP sites. It is a DOS TSR program which uses packet drivers to provide TCP/IP services.