Moreover, this work presents a method that allows to evaluate and to compare different strategies of preservation. The narrative focus of the text is on preservation and longevity of the digital material, therefore it loads obtains a structural problem that at risk places the longevity of the digital information. It leads in account that the digital document can have some copies without losing the quality. But, for having the technological dependence each more necessary time, it becomes also vulnerable the digital document the fast obsolescence the one that the technology always presents although to add new forms of demonstration. The main chapters are divided in subjects as: the main strategies of digital preservation that if subdivides in sections on technology preservation, cooling process, emulation, migration/conversion, migration for analogical supports, update of versions, conversion for competing formats, normalization, migration the order, distributed migration, encapsulamento, the rock of digital Rosetta. It has other chapters as directories of formats, authenticity, goal preservation information, evaluation of preservation strategies, and synthesis and conclusion. On the technology preservation, it consists of the conservation of the technological context, through the conservation and maintenance of all the necessary hardware and software to the correct presentation of digital objects. It is treated, over all of the creation of technology museums.

The cooling process section is the platform change, that is, the transference of one information physical support of storage for the other most current one before the first one if spoils or if becomes irremediably obsolete. In the Emulation, the author if relates to the use of a software, assigned emulator, capable to reproduce the behavior of a platform of the hardware and/or old software, in the one other most current one. In this technique, installs a emulator-software in the current computer that has current and new architecture, so that the current machine reads and works the old platform.