Natural Data Storage: A Review on sending Information from now to then via Nature <s> INTRODUCTION <s> The rapid development of the Internet, fast drop of storage cost, and the great improvement of storage capacityhave created an environment with an enormous amount of digital data. In addition to the traditional goals like performance, scalability, availability, and reliability, other challenges including manageability, searching for the desired information, energy efficiency, long-term data preservation, and data security become increasingly important for storage systems. We first present the evolution path of the past development of storage systems. The impact of the advancement of disk technology on fault tolerance is discussed next. The potential solutions and research issues of the new challenges are also briefly discussed. <s> BIB001 </s> Natural Data Storage: A Review on sending Information from now to then via Nature <s> INTRODUCTION <s> This article surveys all known fields of network coding theory and leads the reader through the antecedents of the network coding theory to the most recent results, considering also information theory and matroid theory. By focusing on providing ideas and not formulas, this survey is both fitted for the taste of readers who are mathematically oriented and newcomers to the area. Additionally, this survey also includes an innovative and clear graph representation of the most prominent literature on network coding theory, its relevance and evolution from the very beginning till today. <s> BIB002 </s> Natural Data Storage: A Review on sending Information from now to then via Nature <s> INTRODUCTION <s> Digital production, transmission and storage have revolutionized how we access and use information but have also made archiving an increasingly complex task that requires active, continuing maintenance of digital media. This challenge has focused some interest on DNA as an attractive target for information storage because of its capacity for high-density information encoding, longevity under easily achieved conditions and proven track record as an information bearer. Previous DNA-based information storage approaches have encoded only trivial amounts of information or were not amenable to scaling-up, and used no robust error-correction and lacked examination of their cost-efficiency for large-scale information archival. Here we describe a scalable method that can reliably store more information than has been handled before. We encoded computer files totalling 739 kilobytes of hard-disk storage and with an estimated Shannon information of 5.2 × 10(6) bits into a DNA code, synthesized this DNA, sequenced it and reconstructed the original files with 100% accuracy. Theoretical analysis indicates that our DNA-based storage scheme could be scaled far beyond current global information volumes and offers a realistic technology for large-scale, long-term and infrequently accessed digital archiving. In fact, current trends in technological advances are reducing DNA synthesis costs at a pace that should make our scheme cost-effective for sub-50-year archiving within a decade. <s> BIB003 </s> Natural Data Storage: A Review on sending Information from now to then via Nature <s> INTRODUCTION <s> The sophisticated tools and techniques employed by Nature for purposeful storage of information stand in stark contrast to the primitive and relatively inefficient means used by man. We describe some impressive features of biological data storage, and speculate on approaches to research and development that could benefit the storage industry in the coming decades. <s> BIB004 </s> Natural Data Storage: A Review on sending Information from now to then via Nature <s> INTRODUCTION <s> Information, such as text printed on paper or images projected onto microfilm, can survive for over 500 years. However, the storage of digital information for time frames exceeding 50 years is challenging. Here we show that digital information can be stored on DNA and recovered without errors for considerably longer time frames. To allow for the perfect recovery of the information, we encapsulate the DNA in an inorganic matrix, and employ error-correcting codes to correct storage-related errors. Specifically, we translated 83 kB of information to 4991 DNA segments, each 158 nucleotides long, which were encapsulated in silica. Accelerated aging experiments were performed to measure DNA decay kinetics, which show that data can be archived on DNA for millennia under a wide range of conditions. The original information could be recovered error free, even after treating the DNA in silica at 70 °C for one week. This is thermally equivalent to storing information on DNA in central Europe for 2000 years. <s> BIB005
With the extensive use of social networking and cloud computing, there is a paradigm shift in the volume of data produced. It is estimated that by 2020, 35 Zettabytes of digital information will be generated  . This highlights a big concern of storing and maintaining the rapid growth of data that enforces the data storage experts to design a new architecture to store the data  ] BIB001 . Steming from the early days storage medium like rocks, stones, paper, punch cards, magnetic tapes, CD, DVD, floppy disk, etc. to the modern days distributed cloud data storage  [  BIB002 ; there is a drastic advancement in the data storage devices (as depicted by Figure 1 ). But these magnetic and optical discs are big, need to be maintained regularly and are prone to decay. Also they are not environment friendly as they consume vast amount of energy and release lots of heat. Scientist are trying to miniaturize the size of silicon chips up to many folds but this makes it more expensive. Alternatively, researchers instigate the use of living source from nature to preserve the data which give birth to biostorage. Biostorage is the field of storing and encrypting information in living cells or natural medium (see Fig 2)  . Comparison of natural storage medium and digital storage devices is appraised in BIB004 ]. Many natural storage medium like DNA, protein, bacteria have been explored. This review paper showcase the evolution of DNA based storage systems along with its information encoding methods in details. Though there are evidences of reliable and scalable DNA based information systems, recent works by Church et al  ], Goldman et al BIB003 and BIB005 improved the efficiency of data encoding in DNA, which indicates the right time for the coding and information theorist communities to work on the challenges in natural data storage systems. Through this paper, one can witness the potential and challenges of DNA based information storage as well as other natural storage like bacterial and protein based storage systems. This review is structured as follows. Section 2 introduce the DNA based information storage system. Section 3 give brief description about bacterial data storage. Section 4 describes the protein as hard drive. Section 5 highlights the experimental evidence and challenges. This paper concludes with general remark. 