Inside Windows® Server 2003

Side-by-Side Assemblies

RAM has historically been an expensive commodity, so Microsoft has always designed Windows to be frugal with memory. (Well, if not frugal, at least to gobble it with something less than the conspicuous consumption of a Roman Caesar.)

One way of conserving memory is to share the image of a DLL loaded by one process with other processes. This DLL sharing can cause no end of headaches, as I'm sure you're aware. For instance, a DLL installed by an application might be a version that lacks a function used by another application. If the second application launches after the first, it links to the DLL image that's already in memory. When it makes the ill-fated call to the missing function, the result is generally not pretty. ...