The Windows Installer (previously known as Microsoft Installer) is a software component used for the installation, maintenance, and removal of software on modern Microsoft Windows systems. The installation information, and often the files themselves, are packaged in installation packages, loosely relational databases structured as OLE COM Structured Storages and commonly known as "MSI files", from their default file extension. Windows Installer contains significant changes from its predecessor, Setup API. New features include a GUI framework and automatic generation of the uninstallation sequence. Windows Installer is positioned as an alternative to stand-alone executable installer frameworks such as older versions of InstallShield and Wise (later versions of both products are based on Win