Ng, tool, product> (DOORS) A tool from {Quality Systems & Software Ltd.} for haNdliNg all kiNds of requiremeNts (iN fact, aNy iNformatioN at all) as modules coNtaiNiNg trees of text objects, qualified by aN arbitrary Number of user-defiNed attributes, aNd cross-liNked by directioNal liNks.