Mobile shed originated in the island country of Japan. Because of Japan's small land area, the use of compact shelves can save more than 70% of the space, also known as compact shelves. Dense cabinets have developed rapidly in Japan, and the Japanese understand it as a movable shelf, which is widely used in enterprise stores. In 1980s, with the reform and opening-up, dense cabinets were introduced into China as luxury goods. It appears in the offices of large state-owned enterprises as a substitute for filing cabinets. Later, some large domestic enterprises quickly copied it. Among them, the earliest production bases were Luoyang, Shenyang, the old industrial bases at that time, and Ningbo and other places along the coast ... With the rapid development of modern society, information materials are increasing, which brings convenience to people's use and information exchange, but also brings new problems to storage, access and management. The appearance of dense cabinets solved this problem for us. With the advantages of large storage capacity, convenient use, space saving and convenient management, it has become the best choice for national government departments and large enterprises and institutions to store data. It is developed and produced according to the industry standard DA/T7-92 of the National Archives Bureau and the national standard GBT 13667.3, and is suitable for storing books, materials, archives, commodity prices, documents and financial vouchers in reference rooms, archives and sample rooms of government agencies, enterprises and institutions. Compared with traditional bookshelves, bookshelves and document racks, it has large storage capacity and saves space.