Читать книгу Archives in the Digital Age - Abderrazak Mkadmi - Страница 25

Storage, or what is sometimes called archiving (in the primary sense of the term), supports the conservation of documents over time. In order to implement an effective storage solution, it is first necessary to establish a needs analysis related, in particular, to the volume of data, their importance, the frequency of their consultation, the degree of confidentiality, the degree of importance of security, the length of time they are kept and the interest of putting them online, among other factors.

To facilitate the different needs of this conservation function, an ERM system uses several storage media, according to the following criteria:

 – criteria relating to the document: types of documents, frequency of consultation, interest in having it online and retention periods;

 – criteria relating to the medium: document access time, storage capacity, cost, rewritability or non-rewritability and secure access.

There are several storage media that can be classified into generations:

 – First generation media are considered to be analog media and have not been used since the late 1990s. This refers to the perforated card and perforated tape system, which originated in the 18th century. Their storage capacity is very small and is measured in a few tens of bytes.

 – Second generation media are magnetic media and have a digital recording mode, except for magnetic tape, which has both analog and digital recording modes. They include magnetic tape, cassette, hard disks, cartridges and diskettes. These media have, however, been able to withstand technological developments over a long period of time [FLE 17].

 – Third generation storage media are considered to be recordable digital optical media. We are talking about CDs (Compact Disk), DVDs (Digital Video Disk) and Blu-ray disks, also known as BDs7. In today’s market, we are talking about several new optical media such as glass discs, M-Disc (the main characteristic being that the burning layer is made of synthetic diamond) and nanoform (a disk that has a very high resistance to damage).

 – Fourth generation storage media are considered removable storage media (flash memory). This refers to USB (Universal Serial Bus), SD (Secure Digital), microSD, SSD (Solid-State Drive) and so on. The advantages of this type of media lie in its high speed access and storage capacities, which are close to those of a “classic” hard disk, the case of SSDs.

 – Storage media under development are revolutionary storage media that should offer high storage capacity and high access speed, such as DNA (deoxyribonucleic acid), which is the hereditary genetic material of all living species on the Earth. According to the researchers, we estimate that the information stored on this support could be preserved over hundreds of thousands of years [CHU 12, COL 14]. Another equally revolutionary medium is quartz, which has proven its solid thermal resistance.