Windows Instability Isn't as Simple as "DLL Hell"

“DLL Hell” is a catchall phrase that describes two major software installation-related problems on Windows PCs. The first problem is that installing new software, updating existing software, or de-installing existing software too often “breaks” a previously stable system. The second problem is that if it is possible to devise steps to consistently install a new piece of code “safely,” the steps are likely to be extremely time consuming and must be followed in precisely the right order to maintain system stability.

The technical causes behind software installation instability go well beyond what the name “DLL Hell” implies—conflicts between incompatible versions of Dynamic Link Libraries (DLLs). Other technical issues that contribute to the problem include unclear ownership of the operating system (OS) directory, service packs loaded with new features, and option packs rushed to market without adequate testing.

DLL Incompatibilities

Microsoft’s DLLs were a laudable effort, introduced in the early days of Windows, to create shared software components. Disk space and memory configurations were tight in the early 1990s. Offering developers prebuilt libraries with functions they could call from their own applications, economized on the amount of code an application had to install on the system, and eliminated the need for programmers to “reinvent the wheel” by writing their own functions from scratch. When managed properly, this is a perfectly sound strategy, since component sharing greatly simplifies and speeds coding and testing. However, the devil is in the details, and failures in implementation caused unpleasant side effects.