Reversible ablative recording

Figure 7.9. The reversible ablative recording process in a dye-polymer medium overcoated with a thin restraining layer. The capping layer (CAP L.), recording layer (EEC. L.), reflective layer (REF. L.), and surface smoothing layer (S.S.L.)...

After speaking immediately to an FBI agent, he sought records from the government but was advised that there was no record of any Wayne Ritchie serving as a deputy marshal in 1957. This Kafkaesque denial of his existence was only reversed when he was able to produce W-2 forms from 1957. Then, he received 20 pages of employment records including his service in the Marines and at Alcatraz. 

It is evident that our globalized world is based on informatics and communications, and both technologies are supported by the existence of fast computers. However, it is often overseen that an essential part of the computer is its memory. A computer memory should be able to store huge amounts of data moreover, they must be accessible in an easy and fast way and occupy a reduced volume. An information bit recorded in a memory must be able to remain unspoiled for about 10 years, and be read or written reversibly in a minimum of time. At present, the only materials that fulfill all these requirements are magnetic materials. 

Application Incompatibility. Records developed in one application may not be functionally compatible with another application even though both have the same operating role. For example, one vendor s CADD software may not be able to read another vendor s CADD software data (even though the reverse transaction may be possible). As a result, migrations in applications either over time or between facilities can be problematic in operating practice. This kind of compatibility erosion can challenge continued operations. 

In the early fifties by using the recording spectrophotometers the chemist was able to approach his problem in a new way, viz. by starting off with a known chromophoric system and modifying it to yield other known chromophoric systems. In this way he was able to map increasingly larger portions of the molecule under study. If the reactions were reversible he stood to gain in addition valuable stereochemical information. Some of the basic operations for tetrahydro-/S-carboline alkaloids are indicated in Chart 3.4 and their success or failure in a practical test could be a combination of stereochemistry and/or the absence of the depicted system. 

---