Flash memory devices are winning the competition for storage density against magnetic recording devices. This outcome results from advances in physics that allow storage of more than one bit per cell, coupled with advances in signal processing that reduce the effect of physical instabilities. Constrained codes are used in storage to avoid problematic patterns. Recently, we introduced binary symmetric lexicographically-ordered constrained codes (LOCO codes) for data storage and transmission. This paper introduces simple constrained codes that support non-binary physical gates in multi, triple, quad, and the currently-in-development penta-level cell (M/T/Q/P-LC) Flash memories. The new codes can be easily modified if problematic patterns change with time. These codes are designed to mitigate inter-cell interference, which is a critical source of error in Flash devices. The new codes are called q-ary asymmetric LOCO codes (QA-LOCO codes), and the construction subsumes codes previously designed for single-level cell (SLC) Flash devices (ALOCO codes). QA-LOCO codes work for a Flash device with any number, q, of levels per cell. For q ≥ 4, we show that QA-LOCO codes can achieve rates greater than 0.95log 2 q information bits per coded symbol. Capacity-achieving rates, affordable encoding-decoding complexity, and ease of reconfigurability support the growing improvement of M/T/Q/P-LC Flash memory devices, as well as lifecycle management as the characteristics of these devices change with time.
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Fluorescent materials-based information storage
The third industrial revolution has brought mankind into the information age. The development of information storage materials has played a key role in this transformation. Such materials have seen use in many application areas, including computing, logistics, and medicine. Information storage materials run the gamut from magnetic information storage media to molecular-based information storage materials. Among these, fluorescent-based information storage materials are of particular interest due to their unique properties, including an ability to store information with high levels of security, maintain mechanical stability, and respond to appropriately chosen external stimuli. In this review, we focus on recent advances involving the preparation and study of fluorescent materials-based information storage codes. For organisational purposes, these codes are treated according to the dimensionality of the code system in question, namely 1D-, 2D-, and 3D-type codes. The present review is designed to provide a succinct summary of what has been accomplished in the area, while outlining existing challenges and noting directions for future development.
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- Award ID(s):
- 1807152
- PAR ID:
- 10170776
- Date Published:
- Journal Name:
- Materials Chemistry Frontiers
- Volume:
- 4
- Issue:
- 4
- ISSN:
- 2052-1537
- Page Range / eLocation ID:
- 1024 to 1039
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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