Data storage media

Archived electronic data are to be treated no differently to archived paper data. An archivist should be assigned, access should be limited to authorized personnel, data should be archived at the completion of the study, and all material should be indexed to permit expedient retrieval. Depending on the medium used for storage, an area within the facility may be needed with specific environmental controls to maintain the integrity of electronic data. This should be specified in the data storage SOPs. Environmental conditions need to be monitored in the archives where electronic media are stored. 

This procedure allows filling pressure in the vehicle tank of 35 MPa to be attained even if the pressure in the low- and medium-pressure storage bank is well below this value. These data are suitable, if the temperature of the gas can be held at 15 °C. Because of the temperature increase during fast fill operation, an overpressurisation is needed to achieve the maximum fill at nominal conditions (35 MPa at 15°C). 

Examples of archiving include on-line systems and storage on external systems. Appropriate measures must be taken to ensure data availability and integrity. In particidar, it must be checked whether a different medium data format is necessary for the archiving period. This may require associated hardware and software to be kept, along with the necessary operating documentation. 

Network Transport medium for moving the data from the instrument to a server for secure data storage. 

The problem with the application of these changes in optical properties for optical data storage is that the significant drop in reflectivity upon the first UV irradiation is related to an irreversible structural change. So the film can be used a as write-once medium only. Furthermore, the sensitivity of the system is low, so writing the information takes a rather long time. The changes in the optical properties in subsequent irradiation cycles are reversible, but they are connected with the unstable cis-isomer, which renders the inscribed information volatile. 

Photochromic materials have been developed in order to dramatically increase the memory density. These materials can be used for photon-mode recording, which is based on the photochemical reaction of the medium. In photon-mode recording, light characteristics such as wavelength, polarization, and phase can be multiplexed in data storage and thus can, in a potentially dramatic ways, increase the memory density. 

Figure 3.88. Composition of a multilayer optical data storage medium photosensitive layer of about 1-p.m thickness (1), nonphotoactive polymer as separating layer of 30-pm thickness (2), and glass substrate (3) [244],...

---