Storing shared documents that are customized by users in cloud computing

摘要

The present research aims at introducing a new efficient approach to store shared text documents, which are individually replicated and customized by users, in a cloud server. The approach is applicable to all text file formats supported by any existing application. We assume a text document consists of both text and images. Instead of replicating text of the original document, two tiny intermediate files for each user are generated and stored. Formatting data and comments are produced and saved in a spreadsheet document and a new file format ".comment" respectively. The first file is a spreadsheet document that contains metadata about customized information including highlighted and underlined (and other formatting styles like strikethrough, bold and italic) parts of the document. The other file aims to store comments provided by user in a ".comment" file format. Furthermore, the approach addresses efficiently storage of annotated images inside the document. For this, an algorithm is proposed to store the difference between the annotated and the original images. Whenever a user wants to access his/her customized document, the intermediate files are attached to the original document and appeared to him/her. Finally, we evaluate the proposed approach through a real scenario. The experimental results show a large amount of disk space are saved.