Author Archives: Michal Necasek

Windows Presentation Manager

Posted on January 17, 2011 by Michal Necasek

Any programmer even passingly familiar with the Windows and Presentation Manager APIs is aware that there are significant similarities. When other windowing APIs, such as X11 or Mac OS, are taken into consideration, Windows and the Presentation Manager look like … Continue reading →

Posted in OS/2, Windows | 14 Comments

Installing OS/2 Warp in a Virtual Machine

Posted on November 3, 2010 by Michal Necasek

Installing OS/2 Warp in a virtual machine isn’t difficult, but there are a few pitfalls. The issues are easy to work around, but sometimes quite difficult to diagnose, especially for users not intimately familiar with OS/2. In general, the problems … Continue reading →

Posted in OS/2, VirtualBox, Virtualization | 46 Comments

MS OS/2 Patents

Posted on October 18, 2010 by Michal Necasek

When Microsoft OS/2 1.3 boots up, it prints a prominent message “U.S. Patent No. 4779187; 4825358”. What are those patents? As it turns out, it’s really just one invention, which for reasons perhaps clear to a patent lawyer was essentially … Continue reading →

Posted in OS/2 | 4 Comments

Installing Windows NT 3.x in VirtualBox

Posted on October 12, 2010 by Michal Necasek

All Windows NT 3.x versions can be used in VirtualBox, although they are not officially supported (unlike all following NT versions) and no Guest Additions are provided. Furthermore, for Windows NT 3.1 and 3.5, an extra step needs to be … Continue reading →

Posted in NT, VirtualBox, Virtualization | 22 Comments

Why OS/2 is Hard to Virtualize

Posted on August 5, 2010 by Michal Necasek

For a number of reasons, OS/2 is surprisingly difficult to virtualize, much more so than DOS, Windows 3.x, Windows NT, Windows 95, or many variants of UNIX. Most of these reasons have to do with OS/2’s architecture and history. To … Continue reading →

Posted in OS/2, Virtualization | 6 Comments

The Importance of EMM386

Posted on August 4, 2010 by Michal Necasek

It is fairly obvious that Compaq’s Deskpro 386 changed the PC hardware and was probably one of the major reasons why we aren’t using PS/2 compatibles today. It may be less obvious that CEMM, an offshoot of the Deskpro 386 … Continue reading →

Posted in DOS | 6 Comments

NT and OS/2

Posted on July 26, 2010 by Michal Necasek

OS/2 and Windows NT have an interesting and checkered common history. Until late 1990, the operating system eventually released as Windows NT was known as NT OS/2. Despite its name, NT had very little in common with OS/2 as it … Continue reading →

Posted in NT, OS/2 | 8 Comments