Category Archives: PC history

86-DOS Was an Original

Posted on August 10, 2012 by Michal Necasek

In case it wasn’t sufficiently obvious already: A forensic expert now confirmed that 86-DOS, née QDOS, and (by extension) MS-DOS were not copies of CP/M, either on source or binary level. This comes hardly as a surprise, despite years (nay, … Continue reading →

Posted in DOS, Microsoft, PC history | Leave a comment

Another witness against WordStar

Posted on August 2, 2012 by Michal Necasek

Previous posts examined the question why IBM implemented the A20 hardware in the PC/AT, causing endless headaches to future PC hardware and software developers. WordStar emerged as a possible culprit, but no one would quite point the finger at it. … Continue reading →

Posted in DOS, PC history | 7 Comments

Redirectors and DOS 3.0

Posted on June 3, 2012 by Michal Necasek

When attempting to determine when exactly the network redirector interface was introduced in DOS, the situation seems to be quite clear. Available literature agrees that DOS 3.1 (released in April 1985 by IBM, possibly earlier by Microsoft OEMs) was when … Continue reading →

Posted in DOS, Networking, PC history | 7 Comments

From a Feature to a Bug

Posted on April 6, 2012 by Michal Necasek

Sometimes the quest for backwards compatibility has unintended consequences. In some cases, the presumably beneficial backwards compatibility turns into a source of problems. The costs end up far outweighing the benefits, yet the “feature” may be difficult to get rid … Continue reading →

Posted in DOS, PC history, Windows | 13 Comments

Operating System/2 announced 25 years ago

Posted on April 1, 2012 by Michal Necasek

On April 2nd of 1987 (not April 1st, that wouldn’t do!), IBM and Microsoft jointly announced Operating System/2, the long-awaited protected-mode version of DOS. However, OS/2 was not the only product announced on that day. OS/2 was merely one part … Continue reading →

Posted in IBM, Microsoft, OS/2, PC history | 27 Comments

Lotus 1-2-3 R3 copy protection

Posted on March 17, 2012 by Michal Necasek

Release 3 of Lotus 1-2-3 (1989) utilized a mild form of copy protection which relied partially on technology but primarily on shaming would-be pirates. 1-2-3 installed from copied disks prominently showed the name of the original owner every time the … Continue reading →

Posted in DOS, OS/2, PC history | 4 Comments

Retro development with aclock

Posted on January 29, 2012 by Michal Necasek

In the past few days, I embarked upon a project to port Antoni Sawicki’s aclock, a small text-based clock program (aclock stands for analog clock), to 16-bit Windows. While aclock itself has been ported to over 150 platforms, it is a … Continue reading →

Posted in Development, PC history, Windows | 10 Comments

What’s in a name… OS/2 or DOS?

Posted on January 27, 2012 by Michal Necasek

There have been many rumors that the name “OS/2” was chosen only shortly before the product was announced. It’s not entirely clear what the name would have been otherwise, but quite likely DOS 5; certainly DOS in some form. There … Continue reading →

Posted in Documentation, DOS, OS/2, PC history | Leave a comment

How to make sure your program doesn’t run on Windows 95

Posted on January 24, 2012 by Michal Necasek

For Christmas, I bought myself the book The Old New Thing by Raymond Chen, a long-time Microsoft programmer. The purchase was spurred by discovering, through Google Books, an excerpt of a riveting description of how various software titles abused the DPMI … Continue reading →

Posted in PC history | 4 Comments

Running 1-2-3 R3 in a VM

Posted on October 22, 2011 by Michal Necasek

I recently tried to install the infamous Lotus 1-2-3 Release 3 from 1989 in a VM. The program disks included both DOS and OS/2 executables, and both were failing. The DOS version stopped with “Cannot initialize system driver” immediately after … Continue reading →

Posted in DOS, PC history, VirtualBox | 3 Comments