信手拈来 妙手偶得

The system is used for managing the video files,mp3 files,e-books and pictures in different directories.How do you design it?

Requirements:

1.do not change the files' name or path,you also mustn't make a duplicate copy of any file.
2.do not use relatiionship databese as your persistence solution.
3.You can use different tags to classify the files,one tag could include many files,a file maybe has many tags.
4.Any folder could have its own tags.
5.User can change,delete the tags.
6.User can search the files by path,name and tags.
7.Use seperate pages to show the files,if possible, please show the file on the screen directly.
8.Speed musn't be slower than 50% of acdsee according to the same files.
9.The files in a folder maybe change,such as add more,delete some files,modify.Please  think about it.

I think the system is difficult but very valuable,it is worthwile for us to archetect a perfect solution.