Simple Document Management System is a document repository system.
Version: 1.1.4SDMS is an open-source system that allows you to store any document in a database via a bunch of webpages.
Operating System: Linux
That was the short description, now comes the long one. SDMS uses PHP to provide you with a pretty interface to a MySQL server that allows you to store and retrieve documents and to share those documents between users.
In addition, the system uses ACL (Access Control Lists) to grant access rights to documents on a per-user basis.
So what is all this good for? Well, it for instance allows you to distribute project documentation on a need-to-know basis, whilst keeping a central repository of documents that is accessible to all team members and easy to manage.