Category Archives: Development

Learn Something Old Every Day, Part III

As part of a hobby project, I set out to reconstruct assembly source code that should be built with an old version of MASM and exactly match an existing old binary. In the process I learned how old MASM versions … Continue reading

Posted in Assembler, Development, Microsoft, PC history | 11 Comments


A number of years ago, an 8″ disk containing Seattle Computer Products (SCP) 86-DOS 1.0 was successfully imaged. The newest files on the disk are dated April 30, 1981, making the disk the oldest complete release of what was soon … Continue reading

Posted in Development, DOS, IBM, PC history | 11 Comments

MS LAN Manager NDDK Anyone?

For R&D purposes, I would very much like to get my hands on the circa 1991 Microsoft LAN Manager Network Device Driver Kit which was meant to support the development of NDIS 2.0 drivers. While it is obvious that some … Continue reading

Posted in Development, DOS, Microsoft, Networking, OS/2 | 9 Comments

Complications, Complications

The other day someone asked how hard it would be to modify the Open Watcom linker, wlink, to properly support exports from IOPL segments in OS/2 LX modules. Not terribly hard it turned out, all it needed was to emit … Continue reading

Posted in Development, OS/2, Watcom | 2 Comments

How Old Is OMF?

The Object Module Format (OMF), used by most DOS development tools, and eventually displaced by COFF/ELF in the 32-bit world, is quite old. It is a somewhat strange format because of its age, and it is quite complex, both because … Continue reading

Posted in Development, Intel, Microsoft, PC history, x86 | 8 Comments

EMM386 and VDS: Not Quite Working

The other day I set out to solve a seemingly simple problem: With a DOS extended application, lock down memory buffers using DPMI and use them for bus-mastering (BusLogic SCSI HBA, though the exact device model isn’t really relevant to … Continue reading

Posted in Bugs, Development, DOS Extenders | 2 Comments

Realia SpaceMaker

A recent exploration of Microsoft’s EXEPACK posed the question whether EXEPACK was the first executable compressor, at least in the world of PCs. It wasn’t. That distinction almost certainly belongs to Realia SpaceMaker, which was probably released sometime in late … Continue reading

Posted in Compression, Development, PC history | 12 Comments

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 | 21 Comments

IBM OS/2 1.x Programming Documentation Added

IBM’s programming documentation (Programming Tools and Information, aka PTI) for OS/2 versions 1.2 and 1.3 has been added. Big thanks to Bob Eager who scanned the originals and converted them to PDF. The documents have been added to the OS/2 … Continue reading

Posted in Development, Documentation, IBM, OS/2 | 2 Comments

UINT32_C Macro Considered Harmful

The C99 family of INTN_C and UINTN_C macros fills a real gap in the language, but it also lays extremely nasty traps for the unwary. The evolution of how the macros are defined in the C99 language standard shows that … Continue reading

Posted in C, Development | 2 Comments