3.0 Introduction
You have already learned about the concept of open access in the previous units. The emergence of open access particularly since 2000 has given rise to development of many distributed repositories following varieties of hardware and software solutions according to the objectives of the repositories. These resulted in problems to the users to access the contents of those repositories individually which may be expensive. To overcome the problems, technological solutions in the form of harvesting have been developed. This unit provides you an insight into the harvesting and standards available in the context of open access repositories. In the present system of publication, scholarly output is obscuring its institutional origins. The reason for it is quite simple - much of the intellectual output and value of an institution's intellectual property is diffused through thousands of scholarly journals and other forms around the world. An institutional repository consolidates the intellectual product created by organizations’/ universities’ researchers, making it easier to demonstrate its scientific, social and financial value. These emerging knowledge entities are contributing greatly in developing Open Access Knowledge Movement. Open Access Knowledge System is based on a set of principles and methodologies related to the production and distribution of knowledge objects with the philosophy of openness. Knowledge objects include Data (scientific, technical, historical, geographic or otherwise), Contents (such as journal papers, reports, patents, books, and other artifacts) and General information (including information services). Open access knowledge system can be considered as a superset of open data, open content, open access publishing and open learning resources. It is powered by open source software and open standards. Open access publishing is the publication of material in such a way that it is available to all potential users without financial or other barriers. An open access publisher is a publisher, in some cases it may be distributors, producing/distributing such materials. Many types of materials can be published in this manner: scholarly journals (known as open access journals), magazines and newsletters, e-text or other e-books (whether scholarly, literary, or recreational), music, fine arts, or any product of intellectual activity (Lagoze & Sompel, 2003). As a whole the situation is not quite friendly for OA (open access) users. For example, Directory of Open Access Repositories (OpenDOAR) lists a total of 2606 repositories in 2014 on different subjects. These are following varieties of hardware and software solutions according to the objectives of the repositories and local requirements. These resulted in problems to the users to access the contents of those repositories individually which may be expensive. To overcome the problems, technological solutions in the form of harvesting have been developed. It may be applied to both Gold OA and Green OA but presently most of the harvesting services are related with Green path of OA. To handle all these forms and formats of documents centrally we need a worthwhile technology so that we can manage this vast world of knowledge in a centralized system. In this context harvesting mechanism may help us. So we should have a proper and clear concept of the term Harvester.