Category Archives: VirtualBox

Who Knew What When

Posted on June 28, 2024 by Michal Necasek

When Microsoft released the unique early beta build of Multitasking DOS 4, I quickly found out that it does not run in VirtualBox: This was a bit of a surprise, because the more-or-less released versions of Multitasking DOS 4 from … Continue reading →

Posted in 286, DOS, IBM, Microsoft, PC architecture, PC history, VirtualBox | 30 Comments

Windows 9x Video Minidriver Source Code

Posted on June 24, 2022 by Michal Necasek

As promised, here is the source code for the Windows 9x VirtualBox display minidriver. For discussion of the source code, see the included readdev.txt file. The code was developed on a Windows 10 host system. For extra credit, I attempted … Continue reading →

Posted in Development, Source code, VirtualBox, Watcom, Windows 95 | 18 Comments

Windows 9x Video Minidriver HD+

Posted on June 6, 2022 by Michal Necasek

The OS/2 Museum has made available the first version of a display driver disk for Windows 9x running on VirtualBox. The driver uses a linear framebuffer and supports 8/16/24/32bpp modes with resolutions up to 1920×1200 pixels (see more below). The … Continue reading →

Posted in Development, VirtualBox, Watcom, Windows 95 | 64 Comments

NT video miniport UHD

Posted on May 27, 2022 by Michal Necasek

I’ve finally managed to update the previously released NT video miniport. The reason for the update was indirect, hacking up the video “hardware” access code to support other environments. That led me to separate the generic mode set code from … Continue reading →

Posted in NT, VirtualBox | 1 Comment

Installing IBM OS/2 1.0 in a VirtualBox VM

Posted on April 30, 2021 by Michal Necasek

Some time ago I wrote that IBM OS/2 1.0 and 1.1 cannot be installed in a VM due to the way it switches between real and protected mode. At the time I did not realize that there was another obstacle, … Continue reading →

Posted in OS/2, VirtualBox, Virtualization | 18 Comments

SCO UNIX 3.2.0f, Limping Along

Posted on July 17, 2019 by Michal Necasek

For the purposes of ancient TCP/IP and NFS research, I wanted to run old SCO UNIX in a VM. I was able to run XENIX with TCP/IP earlier, but SCO’s NFS (provided, like the TCP/IP stack, by Lachman Associates Inc.) … Continue reading →

Posted in NFS, SCO, Software Hacks, TCP/IP, UNIX, VirtualBox, Virtualization | 14 Comments

IBM XENIX: Two Steps Forward

Posted on March 16, 2017 by Michal Necasek

There are reasons to revisit an old topic. Very old, considering that IBM Xenix 1.0 was released in 1984, well over 30 years ago. To recap, this version of Xenix is unique in that it runs only on 286 processors. It … Continue reading →

Posted in 286, IBM, VirtualBox, Xenix | 22 Comments

IBM XENIX: One Step Forward, One Step Back

Posted on March 29, 2015 by Michal Necasek

A while ago I wrote about why IBM PC XENIX 1.0 can’t work on any CPU other than a 286. But not content to leave well enough alone, I attempted to patch this version of XENIX so that it would … Continue reading →

Posted in 286, 386, IBM, VirtualBox, Xenix | 5 Comments

Windows 8.1 Startup Bugcheck 0xC4

Posted on November 30, 2014 by Michal Necasek

On some systems, both physical and virtual, 64-bit Windows 8.1 as well as Server 2012 R2 consistently crashes with error code (bug check) 0xC4; 64-bit Windows 8 may run on these same systems without trouble. On physical systems, the BSOD … Continue reading →

Posted in Bugs, Microsoft, NT, VirtualBox | 15 Comments

Installing Windows 95 on SCSI in a VM

Posted on September 26, 2014 by Michal Necasek

For the adventurous, it is possible to install Windows 95 in a VM configured with SCSI storage (hard disk, CD-ROM) attached to an emulated BusLogic HBA. This works in VirtualBox, but there’s a catch—the emulated PCI BusLogic HBA must have … Continue reading →

Posted in BusLogic, SCSI, VirtualBox, Windows 95 | 7 Comments