Differences between Windows system versions: MSDN, OEM, RTM, and VOL.

MSDN, OEM, RTM, and VOL editions are different versions of the Windows operating system, each with distinct variations.

1. MSDN Edition (Microsoft Developer Network Edition): This version is designed for developers and IT professionals for development and testing purposes. Subscribers of MSDN can access this version from Microsoft’s developer network, which includes various tools and resources to allow developers to develop and test applications.
2. OEM version (Original Equipment Manufacturer version): This is a version of software pre-installed by computer manufacturers, typically sold with new computers. The OEM version is designed for specific hardware configurations and cannot be reinstalled or transferred to other computers. This version is usually cheaper, but does not include some advanced features and support.
3. RTM version (Release to Manufacturing version): This is the version initially released to computer manufacturers and OEM partners. The RTM version is a fully tested and validated official version, typically provided to partners a few months before the official release of the Windows system. The RTM version is the closest to the final version, but may undergo some minor fixes and improvements before the official release.
4. Volume Licensing version (VOL version): This is a version designed for large-scale deployment by enterprises and organizations, available for purchase through bulk licensing. The VOL version allows organizations to activate and deploy Windows systems across multiple computers using the same license key. This version typically includes additional enterprise features and management tools, but is not intended for individual users.

In general, the MSDN version is suitable for development and testing, the OEM version is intended for preinstallation on new computers, the RTM version is the closest to the final version, and the VOL version is for large-scale deployment by enterprises and organizations.