Category Archives: PC history

Ladders and Dragons

Posted on December 28, 2014 by Michal Necasek

While looking at the Windows 95 disk subsystem, something seemed oddly familiar. The nagging feeling was confirmed by the Windows 95 DDK documentation (a file called BLOCK.DOC). The new Windows 95 layered block device driver model called “Dragon” wasn’t all … Continue reading →

Posted in OS/2, PC history, SCSI, Windows 95 | Leave a comment

IBM Blue Lightning: World’s Fastest 386?

Posted on August 22, 2014 by Michal Necasek

One of the OS/2 Museum’s vintage boards is a genuine Made in U.S.A. Alaris Cougar. These boards were produced by IBM for Alaris and are a bit unusual: There’s a small IBM DLC3 processor in plastic package soldered on board, … Continue reading →

Posted in 386, IBM, Intel, PC hardware, PC history | 62 Comments

Intel 287XL… From 1986? Or 1996?

Posted on June 14, 2014 by Michal Necasek

Many or most readers of this site probably know that most chips (and PCBs) have the date of manufacture stamped on them, almost always indicating the year and week (usually not the actual date) they were made. Especially with PCBs, … Continue reading →

Posted in Intel, PC history | 11 Comments

The IBM PC BIOS and Intel ISIS-II

Posted on May 30, 2014 by Michal Necasek

An interesting question recently popped up: How exactly did IBM build the ROM BIOS for the IBM PC? Knowing what tools were used should make it possible to use the ROM listing published in the IBM PC Technical Reference and … Continue reading →

Posted in BIOS, IBM, Intel, PC history | 44 Comments

PC Tech Journal

Posted on May 29, 2014 by Michal Necasek

One of the better PC magazines back in the day (that is, in the 1980s) was PC Tech Journal (or PCTJ for short), a sister periodical of PC Magazine published by Ziff-Davis. While PC Magazine was targeted at the general computer-buying … Continue reading →

Posted in PC history, PC press | 5 Comments

MS-DOS 1.1, 2.0 Source Code Released

Posted on March 25, 2014 by Michal Necasek

In cooperation with the excellent Computer History Museum in Mountain View, Microsoft released the source code to MS-DOS 1.1, MS-DOS 2.0, and Microsoft Word for Windows 1.1a. Here’s hoping that this is a sign of things to come and Microsoft … Continue reading →

Posted in DOS, Microsoft, PC history | 53 Comments

Preserving Floppies

Posted on July 14, 2013 by Michal Necasek

For many years, software was delivered predominantly on floppies. This was true especially in the world of PCs where by definition (almost) every system contained at least one floppy drive and prior to the mid-1990s and mass arrival of CD-ROMs, … Continue reading →

Posted in PC history, Virtualization | 25 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

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