Category Archives: DOS

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 | 9 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 | 1 Comment

DOS/V graphics text modes and scrolling

Posted on January 22, 2012 by Michal Necasek

I recently ran into an interesting difference in the way various DOS/V versions manage VGA memory. DOS/V of course refers to the Japanese versions of DOS which are capable of running on standard “Western” hardware. Microsoft has a very long … Continue reading →

Posted in DOS, VGA | Leave a comment

Is it so hard to document things?

Posted on October 23, 2011 by Michal Necasek

A few weeks ago I spent a bit of time debugging a program which mysteriously failed under DOS 3.3, although it worked without any apparent problem on DOS 4.0 and later, and there was no indication that it required anything … Continue reading →

Posted in DOS | 66 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

Need for Speed SE video glitch

Posted on October 16, 2011 by Michal Necasek

When attempting to play the classic racing game Need for Speed SE in a virtualized environment (VirtualBox), I was dismayed to discover that all the in-game videos were completely garbled. Curiously, the introductory video played when the game is first … Continue reading →

Posted in DOS, VirtualBox | 8 Comments

WordStar needs address wraparound?

Posted on September 24, 2011 by Michal Necasek

The CP/M compatible interface in DOS was initially documented, later forgotten, and then re-discovered every once in a while. In 1989, John Switzer described parts of the CALL 5 system call interface mechanism in a slightly hysterical article as a “back … Continue reading →

Posted in DOS, PC architecture, WordStar | 11 Comments

Who needs the address wraparound, anyway?

Posted on September 13, 2011 by Michal Necasek

The infamous A20 gate is well known and documented in hair-raising detail. What’s much less well documented is the real purpose of the A20 gate, that is, who actually needs the 8086 address wrap-around to be emulated in the first … Continue reading →

Posted in DOS, PC architecture | 4 Comments

IBM DOS 5.0 QBASIC hangs on non-IBM systems

Posted on September 11, 2011 by Michal Necasek

Much like its predecessors, IBM DOS 5.0 has no trouble running on clone systems, as long as they’re sufficiently compatible. That includes virtual machines. However, the QBASIC.EXE (and consequently EDIT.COM) program dated May 9, 1991 consistently hangs on any non-IBM … Continue reading →

Posted in BIOS, DOS, PC history | 20 Comments

Hang with early DOS boot sector

Posted on September 3, 2011 by Michal Necasek

While installing various versions of DOS for the DOS history series of articles, I was faced with a mysterious problem: Some versions of DOS would hang right away when booting from fixed disk, but not from floppy. I already knew … Continue reading →

Posted in DOS | 32 Comments