Category Archives: DOS

The Oldest OS/2 Executable In the Wild

Posted on March 22, 2013 by Michal Necasek

While researching the history of Microsoft’s segmented-executable linker originally called LINK4.EXE, I came across an OS/2 executable that was publicly released almost a year before the first OS/2 SDK was shipped, and many months before OS/2 was even announced. In … Continue reading →

Posted in DOS, Microsoft, OS/2 | 16 Comments

Fixing Broken LINK4

Posted on March 15, 2013 by Michal Necasek

The recently-mentioned multitasking DOS 4 disk images came with a linker called LINK4.EXE. The ‘4’ in fact stands for ‘DOS 4’, although most people who used LINK4 never saw multitasking DOS 4 (LINK4 was shipped with 16-bit Windows SDKs). LINK4 was … Continue reading →

Posted in DOS, Microsoft | 5 Comments

Multitasking MS-DOS 4.0 Lives

Posted on March 11, 2013 by Michal Necasek

Something rather unexpected happened over the weekend: disk images of the near-mythical multitasking DOS 4 suddenly popped up. This is “MS-DOS Version 4.00”—from 1985. It looks almost exactly like MS-DOS 3.0, with COMMAND.COM, FORMAT, SYS, FDISK, JOIN, SUBST, ATTRIB, and … Continue reading →

Posted in DOS, Microsoft | 40 Comments

Book Review: DOS Internals

Posted on September 21, 2012 by Michal Necasek

A Few Decades Late Book Reviews DOS Internals, by Geoff Chappell Addison-Wesley, March 1994; 768 pages, ISBN 0-201-60835-9; $39.95 DOS Internals is a very unusual book. Written by an academic whose field isn’t computer science, it is a in-depth and … Continue reading →

Posted in Books, Development, DOS, Microsoft | 6 Comments

Book Review: Developing Applications Using DOS

Posted on August 17, 2012 by Michal Necasek

A Few Decades Late Book Reviews Developing Applications Using DOS, by Ken W. Christopher, Jr., Barry A. Feigenbaum, and Shon O. Saliga John Wiley & Sons, February 1990; 573 pages, ISBN 0-471-52231-7; $24.95 Developing Applications Using DOS is a surprisingly obscure … Continue reading →

Posted in Books, DOS, IBM | 2 Comments

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 | 6 Comments

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, WordStar | 17 Comments

Phantom 3.0

Posted on July 13, 2012 by Michal Necasek

As previously mentioned, the OS/2 Museum adapted the Phantom redirector example from the second edition of Undocumented DOS to demonstrate that the redirector interface was already fully implemented in the August, 1984 release of PC DOS 3.0, a fact apparently … Continue reading →

Posted in Development, DOS | 36 Comments

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