Category Archives: DOS

Microsoft Editor

(This is a guest post by Antoni Sawicki aka Tenox) In a recent blog post I lamented the lack of a good console/cmd/PowerShell text editor for Windows. During the process I made a rather interesting discovery, that in a fact … Continue reading

Posted in Development, DOS, Editors, Microsoft, NT, OS/2, Source code, Uncategorized | 17 Comments

WordStar Again

While trying to work on my DOS 5.0 article, I looked at DOS 5.0 build 224 from June 1990, which is the oldest surviving beta of DOS 5.0. And the README contains the following intriguing text, which reminded me of … Continue reading

Posted in DOS, PC history, WordStar | 74 Comments


For several years now I’ve been trying to continue the DOS history series and write (or rather finish) a DOS 5 page. While tracing the history of DOS 1.0 or 2.0 is quite difficult and the amount of source material … Continue reading

Posted in DOS, PC history, Random Thoughts | 12 Comments

How to Void Your Valuable Warranty

Try installing Quick Pascal 1.0 on DR DOS 3.40: What is going on there? It’s a long story… In 1988, Microsoft became increasingly worried by a new upstart OS from an old rival, DR DOS. Over the years, Digital Research … Continue reading

Posted in Digital Research, DOS, Microsoft | 30 Comments

There’s Another Possibility

Four years ago we pondered why on Earth a DOS floppy boot sector might start with 69h, supposedly a “direct jump” opcode. Which is the IMUL instruction on 80186 and later, and not documented on 8086. In the meantime, it … Continue reading

Posted in DOS, Floppies | 46 Comments

PC-MOS/386 Source Code

I missed this when it was initially announced. The source code for PC-MOS/386 version 5.01 is now available on github under the GPLv3 license. It requires the user to supply Borland C++ 3.1 in order to build, but there are … Continue reading

Posted in 386, DOS, Source code | 7 Comments

PC DOS 1.0, But Not Quite

Last week a most interesting image of a 160K disk arrived at the OS/2 Museum. The files on the disk image are rather old. When the disk boots up (not trivial, see below), the following message appears: Astute readers will … Continue reading

Posted in DOS, IBM, Microsoft, PC history, Pre-release | 43 Comments

Booting Is Hard

So I had this brilliant idea of using SCSI drives with old 286/386/486 boards which have old BIOSes that can’t handle IDE drives bigger than 500-ish megabytes. The SCSI HBA is the first one I happened to grab, an Adaptec 1542C … Continue reading

Posted in 386, BIOS, CompactFlash, DOS, SCSI | 20 Comments

MS C 4.0 Documentation Added

Another library expansion. This time it’s Microsoft C 4.0 documentation (1986)—because it’s not available online, is not easy to find offline, and because Jeff asked for it. MS C 4.0 was an early Microsoft compiler, implementing first glimpses of the not-yet finalized … Continue reading

Posted in C, Documentation, DOS, Microsoft | 6 Comments

The DOS 4.0 Shell Mouse Mystery

Several years ago, I noticed that in some virtual and physical environments, the DOS Shell in both IBM’s and Microsoft’s DOS 4.0x has a very odd glitch: the mouse pointer moves, but does not register any clicks… except on scroll … Continue reading

Posted in DOS, IBM, PC hardware, PC history | 28 Comments