Installing Software on Microsoft OS

gojericho0

Why is it when you install software on Windows it puts most of the files in the directory you create, but puts others in the Windows or system folders? Why can't it just put everything in one folder?

JDMurray

One upon a time in the MS-DOS days, programs were self-contained and did not normally share files. Every installed DOS program and all of its files lived in separate subdirectories. A program's subdirectory could be easily moved on disk without breaking other programs. Life was simple and good.

Under Windows, it was decided that most applications would share a common set of libraries and run-time files. If Windows apps were installed entirely into a single folder like MS-DOS programs, these files could not be easily shared, and more importantly, expensive disk space would be wasted by redundantly storing identical files in multiple subfolders.

To solve this problem, Microsoft created specific system folders where "shared components" would be stored which multiple programs could use, and "The Registry" to identify what was stored there. This saved disk space, but created a condition known a "DLL Hell," in which one installation overwrote a newer DLL with an older version of the same DLL, possibly breaking other programs. Thus, life was not entirely good (but it created jobs for software and IT people).

With the invention of inexpensive disk space, Windows Vista, and Microsoft .NET, the trend today is to go back to storing each program (almost) entirely into a separate folder one again. If you need to store files in a common area, you will still be able to do that, but it is not a requirement. Technically, it was not a requirement under earlier versions of Windows either, and that was one of the solutions for DLL Hell.

Who knows what operating system design innovations Microsoft will bring us all tomorrow...