Category Archives: DOS

On a dark, rainy night in April 1985…

Posted on July 7, 2012 by Michal Necasek

Update: Since the original document disappeared, a local copy is now provided. When researching the history of computing, from time to time an unexpected gem turns up. The copy of Ray Ozzie’s notes from a 1985 meeting with Microsoft is one … Continue reading →

Posted in DOS, Microsoft, Windows | 39 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 | 14 Comments

MS-DOS OAKs

Posted on May 25, 2012 by Michal Necasek

Prior to 1991, Microsoft did not sell MS-DOS to end users directly. Although MS-DOS 3.2 (1986) and later was available to system builders as a “packaged product”, most PC users would get an OEM version of MS-DOS with a new … Continue reading →

Posted in Development, DOS, Microsoft | 11 Comments

Early Microsoft Networks

Posted on May 18, 2012 by Michal Necasek

Microsoft networking technologies, often referred to as SMB and/or CIFS, have a very long history, longer than one might realize. While Microsoft’s networking products only became somewhat widespread around 1993-1994 with Windows for Workgroups, their history goes back to 1984-1985. … Continue reading →

Posted in DOS, Microsoft, Networking | 17 Comments

DOS boot hang update

Posted on April 27, 2012 by Michal Necasek

Additional information came to light regarding the hangs with DOS 2.x/3.x when booting from a disk with large number of sectors per track. The problem appears to have been noticed sometime in 1987—perhaps. The MS-DOS OEM Adaptation Kit (OAK) for … Continue reading →

Posted in DOS, IBM, Microsoft | 4 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

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