What's the difference between a documented system and a system of documents?
In ISO/TC176/SC2/N1276 (2015) which is a document supporting ISO 9001:2015 is the following statement "It is stressed that ISO 9001 requires (and always has required) a "Documented quality management system", and not a "system of documents".
A system of documents is a collection of documents which has an aim or purpose. One could say that the ISO 9000 family of standards is a system of standards or documents. Each standard in the family serves the purpose of the set of standards, remove any one of those standards and that purpose is unfulfilled assuming they are all essential for coherence.
A documented system can be any type of system that has been documented. Therefore the set of specifications, drawings, handbooks and manuals for making, installing and operating a physical system is a system of documents. But the documents are not the system; it is merely an incomplete description of the system. It’s incomplete because it probably wont describe the science that explains how and why the component parts function or which explains the behaviour of the people who through their interaction with the physical elements, make the system produce outputs that are greater than the sum of its parts.