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Category Archives: Development
Learn Something Old Every Day, Part XII: Strange File Resizing on DOS
Someone recently asked an interesting question: Why do Microsoft C and compatible DOS compilers have no truncate() and/or ftruncate() library functions? And how does one resize files on DOS? OK, that’s actually two questions. The first one is easy enough … Continue reading
Posted in Computing History, CP/M, Development, Documentation, DOS, Microsoft
29 Comments
Learn Something Old Every Day, Part XI: DOS Directory Searches are Bizarre
A while ago I started playing with EMU2, a piece of software which calls itself “A simple text-mode x86 + DOS emulator”. It is indeed relatively simple, only emulating an 8086 (or maybe 80186, with little bits of 80286 here … Continue reading
Posted in Development, DOS, Undocumented
53 Comments
How Not To Release Historic Source Code
This is how to not do it: GitHub Don’t get me wrong, it’s absolutely brilliant that Microsoft was able to release a fairly complete (minus DOSSHELL) source code for MS-DOS 4.00 or 4.01 (see below). As much as it was … Continue reading
Posted in Development, DOS, Source code
82 Comments
Tarbell to Cromemco
While playing around with old versions of 86-DOS, I came across a disk image of 86-DOS 1.14. I ran the older 86-DOS versions in the SIMH simulator which can emulate the Cromemco disk controller supported by 86-DOS. Unfortunately the 86-DOS … Continue reading
Posted in Development, DOS, PC history
16 Comments
From the Annals of Preprocessor Hackery
Over the last few days I’ve been slowly attacking the source code for 386MAX, trying to build the entire product. One of the many problems I ran into turned out to be quite interesting. There are several (16-bit) Windows components … Continue reading
Posted in 386MAX, C, Development, Microsoft
25 Comments
Retro-Porting to NT 3.1
In another useless project, I decided to find out why even trivial programs created with the Open Watcom compiler refuse to run on Windows NT 3.1. Attempting to start an executable failed with foo.exe is not a valid Windows NT … Continue reading
Posted in Development, Microsoft, NT, Watcom
12 Comments
Retro-Porting to OS/2 1.0
A few weeks ago I embarked on a somewhat crazy side project: Make the Open Watcom debugger work on OS/2 1.0. This project was not entirely successful, but I learned a couple of things along the way. The Open Watcom … Continue reading
Posted in Development, IBM, Microsoft, OS/2, Watcom
10 Comments
Unintended Side Effects
I’ve been lately trying to understand and improve the idling behavior of DOS programs and one of my guinea pigs has been the Open Watcom vi editor. While the 16-bit real-mode DOS variant of the editor idles nicely, the 32-bit … Continue reading
Posted in Development, DOS Extenders
1 Comment
IDLE DR-DOS
I have a laptop. Sometimes I run VMs on it, and some of those VMs run DOS. When a DOS VM does not have any power management, the laptop quickly lets me know by kicking up the fan speed. It … Continue reading
Posted in Computing History, Development, Digital Research
11 Comments
Tracking Down a Bug
When I first encountered the Unix vi editor many years ago, I recoiled in horror. It was nothing like the editors I was used to—Borland IDEs, DOS 5.0/6.x EDIT, or OS/2 and Windows editors. But over the years, I learned … Continue reading
Posted in Debugging, Development, DOS, Watcom
14 Comments