Category Archives: Virtualization

IBM OS/2 1.0 in a VM

Posted on March 21, 2014 by Michal Necasek

As previously mentioned, IBM’s OS/2 1.0 and 1.1 is extra unfriendly to modern hypervisors. To recap, there is a curious difference between IBM’s and Microsoft’s kernels in OS/2 1.0/1.1 with regard to mode switching. For reasons that aren’t very clear, … Continue reading →

Posted in IBM, Microsoft, OS/2, VirtualBox, Virtualization | 36 Comments

Preserving Floppies

Posted on July 14, 2013 by Michal Necasek

For many years, software was delivered predominantly on floppies. This was true especially in the world of PCs where by definition (almost) every system contained at least one floppy drive and prior to the mid-1990s and mass arrival of CD-ROMs, … Continue reading →

Posted in PC history, Virtualization | 25 Comments

Virtualizing QNX 2

Posted on March 20, 2013 by tenox

(Note: This is a guest post from Tenox) Enter 1988… around that time Microsoft just released MS-DOS 4.01 and IBM shipped OS/2 1.1. Compare to the others, this OS was years ahead of its time pretty much on every aspect. … Continue reading →

Posted in QNX, Virtualization | 13 Comments

An old idea: x86 hardware virtualization

Posted on May 13, 2012 by Michal Necasek

It is well known that virtualization of the x86 architecture is an old idea. The Intel 386 processor (1985) introduced the “Virtual 8086” (V86) mode, enabling users to run real-mode operating systems as a task within a 32-bit protected-mode operating systems. … Continue reading →

Posted in 386, Intel, Virtualization | 14 Comments

Solaris 2.5.1 and 2.6 crashes on modern Intel CPUs

Posted on April 20, 2012 by Michal Necasek

I recently found that Solaris 2.6 and 2.5.1 does not work when run in a VM on a modern Intel CPU (Sandy Bridge generation Core i7), or to be exact fails most of the time (about nine times out of … Continue reading →

Posted in Solaris, VirtualBox, Virtualization, x86 | 27 Comments

OS/2 Warp installation pitfalls

Posted on November 9, 2011 by Michal Necasek

Recently I had an opportunity to install and update various versions of OS/2 (Warp 3 and later) in virtual machines. In the process I ran into several subtle and not so subtle issues which may be worth recording, complete with … Continue reading →

Posted in OS/2, Virtualization | 12 Comments

Interrupt 68h and EMM386

Posted on June 8, 2011 by Michal Necasek

While working with a modified BIOS image in a virtual machine, I ran into mysterious hangs when trying to load an old version of EMM386.SYS from MS-DOS 4.01. A newer version of EMM386 did not exhibit the problem. A quick … Continue reading →

Posted in BIOS, DOS, Virtualization | Leave a comment

The Fixed Disk Parameter Table

Posted on May 11, 2011 by Michal Necasek

The Fixed Disk Parameter Table, or FDPT, is a structure primarily used by the BIOS in IBM compatible computers, but is also of critical importance to some (especially older) operating systems which do not use the BIOS. The FDPT was … Continue reading →

Posted in BIOS, PC architecture, Virtualization | 3 Comments

Geometry Problems

Posted on May 11, 2011 by Michal Necasek

When introducing hard disk support in the PC/XT back in early 1983, IBM made a very unfortunate design decision: the information about drive geometry was exposed in the BIOS, and even worse, in the boot sector stored on the disk. SCSI … Continue reading →

Posted in BIOS, PC architecture, Virtualization | 2 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