(5) Storage media and format conversion In the information cycle, storage is often regarded as a moving phase, but the storage media and format are not immutable. Once the original information is changed, it may be lost forever. For this issue, the practice of most organizations is to regularly conduct media and format conversions, which generally range from three years to five years. However, this kind of conversion cost is very expensive, and it often faces problems such as data loss and quality degradation. Therefore, once this kind of conversion is going to take place, it is very important to do inspection work.
In media and format conversion, the most accurate requirement is the work of the data center. The Atmospheric Radiation Tracking Center at the Oak Ridge National Laboratory plans to perform a technical update every 4 to 5 years. With each update, the data will be saved using new technologies. This process takes about 6 to 12 months.
(6) Storage technology storage It is necessary to ensure that not only the content of the file is managed and stored in the archiving process, but also the structure of the content is managed and preserved. To achieve this, one must fully consider technical factors.
According to the estimates of the heads of these projects, the hardware/software conversion cycle is between 2 and 10 years. In some new databases, the word processor may be updated once every 2 to 3 years. Some small or graded versions will change frequently. . Although, at the same time, technology vendors will always provide some ways to convert files, it does not in fact solve the fundamental problems caused by hard/software changes. Especially for some information files that use various complicated functions in the original software, it is very likely that many features in the original document will be lost.
In view of the difficulties caused by hard/software updates, general projects have chosen to use mainstream technologies, but this can only guarantee relative stability and ensure some follow-up services that cannot solve the fundamental problems. The loss of information structure is still a headache. The problem.
In this regard, in terms of format, each project has used some methods to save structural information. For journal articles, most projects use TIFF, PDF, or HTML files, where TIFF is used most often, and TIFF images are actual formats that the user sees, but the nested reference information is not actually a hyperlink.
Some years after the publishing system was converted from proprietary format to SGML format, some large publishers used HTML/SGML. NASA used a very complete SGML format, which was converted from a variety of different formats and products. The publisher will actually convert SGML to simpler HTML when it is stored, along with a PDF version of the conversion path. For pure electronic documents, PDF is the most suitable format, it is a copy of the Postscript file format, but it relies on proprietary coding technology. Because of this exclusivity, it is determined that the use of PDF will have an impact on long-term storage, and it cannot constitute a common standard.
Saving the structure of information in the context of text is already difficult, and it is even more difficult in a multimedia environment. Because multimedia files are a combination of multiple hard, software technologies, and content. In this regard, there were also projects in the survey. At the DITT project of the US Department of Defense, they developed a model and software to manage multimedia files. The other was the University of California, San Diego, where they developed the archives. Modularity allows different levels and types of metadata for storage of various data types.
Another key issue for storage is which format the archive version should use, and the original format should be converted to a standard format for storage. For this, different projects have different options. Both AAS and ACS choose the ASCII format of SGML markup, because this format stands in a variety of mediums, is versatile and can be updated regularly, and has little update cost.
(7) Archival Access For archived visits, the above mentioned are all about how to maintain the longevity of information and the continuity of visits. To ensure that digital archive information can always be accessed, access mechanisms, rights management, and security management must be considered.
Because the various technologies in the digital environment are changing, the technologies for users to access the displays are changing. Today, they are still accessed through the Internet and tomorrow they do not know what mechanism they have changed. Therefore, it is necessary to continue to provide readers with new access methods as access technology changes. Of course, at the same time, the original access route should continue to be used.
Another trouble with archiving access is how to manage various rights. What rights do archival files have? What rights do different user groups enjoy? What rights does the author retain? How the access mechanism properly manages these rights through proper metadata. These problems are reflected in the management to include providing or restricting access rights according to the situation, changing access rights standards in the copyright and security standards of the information.
Security and version control issues also affect digital archiving. In the digital environment, information and copying and tampering are so easy that it is often difficult to distinguish whether the immediate information is the original information or "stolen information." To solve these problems, the key is to manage a good copy of the file through metadata, and use watermarks, digital tags, and other anti-counterfeit characters.
I. Conclusion In the field of science, various digital archives are being practiced or brewed. This article is a review of some of the most representative examples, and discusses issues related to digital archiving from various stages of the information cycle. Many of them are inductions of practical experience, or useful attempts in some example operations, such as file storage standards in some projects, principles of information collection, etc., which are a good reference for other archiving work. At the same time, some of the issues exposed in these projects are also waiting for attention in the future digital archiving work. Of course, with the renewal of technology, all aspects of digital archiving will also change, and more experience will follow. I hope that this article and the above examples can play a role in attracting attention.