can be rewritten in a much compact way (with respect of the license). In general, this can reduce significantly the application code, and later the maintenance costs, and programmers can improve their software writing skills. Version numbering A very common solution to this problem is to have a standardized numbering system, wherein software uses a specific number for each version (aka major version), and also a subnumber for each revision (aka minor version), e.g.: 10.1, or 5.7. The major version only changes when programs that used that version will no longer be compatible. The minor version might change with even a simple revision that does not prevent other software from working with it. In cases like this, software packages can then simply request a component that has a particular major version, and any minor version (greater than or equal to a particular minor version). As such, they will continue to work, and dependencies will be resolved successfully, even if the minor version changes. Semantic Versioning (aka "SemVer") is one example of an effort to generate a technical specification that employs specifically formatted numbers to create a software versioning scheme. Private per application versions Windows File Protection introduced in Windows 2000 prevented applications from overwriting system DLLs. Developers were instead encouraged to use "Private DLLs", copies of libraries per application in the directory of the application. This uses the Windows search path characteristic that the local path is always prioritized before the system directory with the system wide libraries. This allows easy and effective shadowing of library versions by specific application ones, therefore preventing dependency hell. PC-BSD, up to and including version 8.2, a predecessor of TrueOS (an operating system based on FreeBSD) places packages and dependencies into self-contained directories in /Programs, which avoids breakage if system libraries are upgraded or changed. It uses its own "PBI" (Push Button Installer) for package management. Side-by-side installation of multiple versions The version numbering solution can be improved upon by elevating the version numbering to an operating system supported feature. This allows an application to request a module/library by a unique name and version number constraints, effectively transferring the responsibility for brokering library/module versions from the applications to the operating system. A shared module can then be placed in a central repository without the risk of breaking applications which are dependent on previous or later versions of the module. Each version gets its own