To achieve open access to scholarly literature, there are two complementary strategies.
I. Open access Journals. Journals that use a funding model that does not charge readers or their institutions for access (subscription or access fees). Users can read, download, copy, distribute, print, search, or link to the full texts of the journal articles. These journals do no longer invoke copyright to restrict access to and use of the material they publish. Instead they use copyright and other tools to ensure permanent open access to all the articles they publish. For the journal publishers, open access brings increased readership and, with that, increased citations, and maximum visibility and impact for a journal's contents. And it means that the best possible dissemination service is being provided for research.
II. Open access repositories. Open access repositories (or archives or digital repositories) contain research output, not only refereed journal articles, but also theses and dissertations, unpublished reports and working papers, conference and workshop papers, books, chapters and sections, multi-media and audio-visual material, learning objects, datasets, software, patents, etc. They might be institutional or thematic. When these repositories conform to standards created by the Open Archives Initiative they are interoperable, forming a global research facility. Common metadata protocol allows other web applications, such as data mining. Scholars and students deposit their research outputs in open repositories – a practice commonly called self-archiving.
More information: see (openoasis.org/images/stories/briefing_papers/Institutional_repositories.pdf) Briefing Paper What are Institutional Repositories? written by Alma Swan for OASIS