Advances in Macromolecular Data Storage
  We propose to develop a new method of information storage to replace magnetic hard disk drives and other instruments of secondary/backup data storage. The proposed method stores petabytes of user-data in a sugar cube (1 cm3), and can read/write that information at hundreds of megabits/sec. Digital information is recorded and stored in the form of a long macromolecule consisting of at least two bases, A and B. (This would be similar to DNA strands constructed from the four nucleic acids G,C,A,T.) The macromolecules initially enter the system as blank slates. A macromolecule with, say, 10,000 identical bases in the form of AAAAA....AAA may be used to record a kilobyte block of user-data (including modulation and error-correction coding), although, in this blank state, it can only represent the null sequence 00000....000. Suppose this blank string of A's is dragged before an atomically-sharp needle of a scanning tunneling microscope (STM). When electric pulses are applied to the needle in accordance with the sequence of 0s and 1s of a 1 kB block of user-data, selected A molecules will be transformed into B molecules (e.g., a fraction of A will be broken off and discarded). The resulting string now encodes the user-data in the form of AABABBA...BAB. The same STM needle can subsequently read the recorded information, as A and B would produce different electric signals when the strand passes under the needle. The macromolecule now represents a data block to be stored in a "parking lot" within the sugar cube, and later brought to a read station on demand. Millions of parking spots and thousands of Read/Write stations may be integrated within the micro-fabricated sugar cube, thus providing access to petabytes of user-data in a scheme that benefits from the massive parallelism of thousands of Read/Write stations within the same three-dimensionally micro-structured device. 
Masud Mansuripur
physics.bio-ph cs.ET