Digital preservation of journals at UNAM and institutional repositories, an approach

The purpose of this document is to provide the experience of migration and digital preservation of technical and scientific journals acquired by purchase at the Autonomous University of Mexico (UNAM). It approaches generally with the characteristics of the printed collections of the UNAM, with updates on these data. In addition, it describes the state of the art regarding print subscriptions with hard data, some of which arise are updated through 2014. Also, it's presented an outline of some digital preservation projects as repositories with the opinion of the UNESCO about it, and then it's described the three major collaborative digital preservation projects with their characteristics, advantages and disadvantages, organized by librarians and publishers together is also provided, and called Portico, LOCKSS and CLOKSS. The UNAM Library System is comprised of 138 libraries. Print periodicals, as in any other library, have a common denominator regarding subscriptions, called missing. This is due to several factors related to logistics edition of sending, receiving and control of subscriptions, which makes getting to users and therefore staff working in the system libraries. One of the major challenges it faces is the changing pattern of acquisition of printed or electronic form over just digital, which makes us think about preserving the acquired. Several models of digital preservation are analyzed to finally determine what is best for the UNAM.