question: How can a microSD card the size of your thumbnail hold 1TB of data?
comment: Transistors store data. Transistors can fit into a 3d-space and can be stacked. Right now transistors are usually ~20nanometers. Human hair is 100000nm. For a 1TB microSD the transistor would need to be ~5nm. Theoretically, a transistor could be as small as a single molecule. You need ridiculously precise manufacturing techniques for these small sizes. At the molecular scale current physics has become a problem. Electrons can only move so fast, and heat waste becomes an issue. Quantum physics comes into play and photon-based computing (rather than electrons) is needed.
passages: With recently demonstrated technology using DNA computing for storage, one yottabyte of capacity would require a volume between 0.003 and 1 cubic metre, depending on number of redundant backup copies desired and the storage density: "Our genetic code packs billions of gigabytes into a single gram". DNA is much more advanced technology than microSDXC cards (for this application) and accompanied by uncertain costs, but this suggests potential information density.
   The Secure Digital Ultra Capacity (SDUC) format, described in the SD 7.0 specification, and announced in June 2018, supports cards up to 128 TiB (140737488355328 bytes) and offers speeds up to 985 MB/s, regardless of form factor, either micro or full size, or interface type including UHS-I, UHS-II, UHS-III or SD Express. The SD Express interface can also be used with SDHC and SDXC cards.
  
  Section::::Capacity.:SDUC.:exFAT filesystem.
   In 2012, DNA was successfully used as an experimental data storage medium, but required a DNA synthesizer and DNA microchips for the transcoding. , DNA holds the record for highest-density storage medium. In March 2017, scientists at Columbia University and the New York Genome Center published a method known as DNA Fountain which allows perfect retrieval of information from a density of 215 petabytes per gram of DNA, 85% of the theoretical limit.
  
  Section::::Effects on performance.
   BULLET::::- MultiMediaCard
  
  BULLET::::- Secure Digital
  
  BULLET::::- Memory Stick, and xD-Picture Card.
  
  A new generation of memory card formats, including RS-MMC, miniSD and microSD, feature extremely small form factors. For example, the microSD card has an area of just over 1.5 cm, with a thickness of less than 1 mm.
  
  NAND flash has achieved significant levels of memory density as a result of several major technologies that were commercialized during the late 2000s to early 2010s.
   The device is described as half the size of a credit card and has an ARM Cortex-M0 processor, accelerometer and magnetometer sensors, Bluetooth and USB connectivity, a display consisting of 25 LEDs, two programmable buttons, and can be powered by either USB or an external battery pack. The device inputs and outputs are through five ring connectors that form part of a larger 25-pin edge connector.
  
  Section::::Hardware.
  
  The physical board measures and, , includes:
   The scientists at IBM Research – Almaden who made the film are moving atoms to explore the limits of data storage because, as data creation and consumption gets bigger, data storage needs to get smaller, all the way down to the atomic level. Traditional silicon transistor technology has become cheaper, denser and more efficient, but fundamental physical limitations suggest that scaling down is an unsustainable path to solving the growing Big Data dilemma. This team of scientists is particularly interested in starting on the smallest scale, single atoms, and building structures up from there. Using this method, IBM announced it can now store a single bit of information in just 12 atoms (current technology takes roughly one million atoms to store a single bit).
   As an alternative to the storage in direct DNA sequence, the data can also be stored in DNA nanostructures. On December 26, 2018, researchers from Cavendish Laboratory, University of Cambridge published a paper in Nano Letters (https://pubs.acs.org/doi/abs/10.1021/acs.nanolett.8b04715) to show the possibility of encoding digital data into DNA nanostructures along double-stranded DNA and reading with solid-state nanopores. This provides an easy writing option with only hundreds of units to form a library of up to 5 × 10^33 (2^112) different molecules to store a large amount of data, which can be easily retrieved using nanopores.
  
  Section::::Davos Bitcoin Challenge.
   A host device can ask any inserted SD card for its 128-bit identification string (the Card-Specific Data or CSD). In standard-capacity cards (SDSC), 12 bits identify the number of memory clusters (ranging from 1 to 4,096) and 3 bits identify the number of blocks per cluster (which decode to 4, 8, 16, 32, 64, 128, 256, or 512 blocks per cluster). The host device multiplies these figures (as shown in the following section) with the number of bytes per block to determine the card's capacity in bytes.
   Section::::Physical representation.
  
  A bit can be stored by a digital device or other physical system that exists in either of two possible distinct states. These may be the two stable states of a flip-flop, two positions of an electrical switch, two distinct voltage or current levels allowed by a circuit, two distinct levels of light intensity, two directions of magnetization or polarization, the orientation of reversible double stranded DNA, etc.
   BULLET::::- Microholas operates out of the University of Berlin, under the leadership of Prof Susanna Orlic, and has achieved the recording of up to 75 layers of microholographic data, separated by 4.5 micrometres, and suggesting a data density of 10 GB per layer.
  
  BULLET::::- 3DCD Technology Pty. Ltd. is a university spin-off set up to develop 3D optical storage technology based on materials identified by Daniel Day and Min Gu.
   BULLET::::- In 2017, Samsung combined its V-NAND technology with eUFS 3D IC stacking to produce a 512GB flash memory chip, with eight stacked 64-layer V-NAND dies. In 2019, Samsung produced a 1TB flash chip with eight stacked 96-layer V-NAND dies, along with quad-level cell (QLC) technology (4-bit per transistor), equivalent to 2trillion transistors, the highest transistor count of any IC chip.
   Multi-level cell (MLC) technology stores more than one bit in each memory cell. NEC demonstrated quad-level cell (QLC) technology in 1996, with a 64Mb flash memory chip storing 2-bit data per cell. STMicroelectronics also demonstrated quad-level cells in 2000, with a 64Mb NOR flash memory chip. In 2009, Toshiba and SanDisk introduced NAND flash chips with QLC technology storing 4-bit per cell and holding a capacity of 64Gb. Samsung Electronics introduced triple-level cell (TLC) technology storing 3-bit per cell, and began mass-producing NAND chips with TLC technology in 2010.
   Section::::Physical properties.
   Section::::Series.:Quantum Bigfoot TS.
  
  The fourth and final series of Quantum Bigfoot drives produced was the Bigfoot TS series. This series retained the spindle speed and interface speed of its predecessor. The main performance enhancement was a reduction in access time, to "less than 10.5 ms." It was produced in capacities of 6.4 GB, 8.4 GB, 10.0 GB, 12.7 GB and 19.2 GB.
   In biological terms, there are 7.2 billion humans on the planet, each having a genome of 6.2 billion nucleotides. Since one byte can encode four nucleotide pairs, the individual genomes of every human on the planet could be encoded by approximately 1x10^19 bytes. The digital realm stored 500 times more information than this in 2014 (see figure). The total amount of DNA contained in all of the cells on Earth is estimated to be about 5.3x10^37 base pairs, equivalent to 1.325x10^37 bytes of information.
   Communication protocols for contact smart cards include T=0 (character-level transmission protocol, defined in ISO/IEC 7816-3) and T=1 (block-level transmission protocol, defined in ISO/IEC 7816-3).
  
  Section::::Design.:Contactless smart cards.
  
  "Contactless smart cards" communicate with and are powered by the reader through RF induction technology (at data rates of 106–848 kbit/s). These cards require only proximity to an antenna to communicate.
   The resulting microserver is fit inside the same form factor as standard FB-DIMM socket. The SoC chip, about 20 GB of DRAM and a few control chips (such as the PSoC 3 from Cypress used for monitoring, debugging and booting) comprise a complete compute node with the physical dimmensions of 133×55 mm. The card's pins are used for a SATA, five Gbit and two 10 Gbit Ethernet ports, one SD card interface, one USB 2 interface, and power.
   Section::::Current practice.:Computer hardware.:Flash drives.
  
  USB flash drives, flash-based memory cards like CompactFlash or Secure Digital, and flash-based SSDs use SI prefixes;
  
  for example, a "256 MB" flash card provides at least 256 million bytes (), not 256×1024×1024 ().
  
  The flash memory chips inside these devices contain considerably more than the quoted capacities, but much like a traditional hard drive, some space is reserved for internal functions of the flash drive. These include wear leveling, error correction, sparing, and metadata needed by the device's internal firmware.
  
  Section::::Current practice.:Computer hardware.:Floppy drives.
   In 1T DRAM cells, the bit of data is still stored in a capacitive region controlled by a transistor, but this capacitance is no longer provided by a separate capacitor. 1T DRAM is a "capacitorless" bit cell design that stores data using the parasitic body capacitance that is inherent to silicon on insulator (SOI) transistors. Considered a nuisance in logic design, this floating body effect can be used for data storage. This gives 1T DRAM cells the greatest density as well as allowing easier integration with high-performance logic circuits, since they are constructed with the same silicon on insulator process technologies.
   As of August 2017, microSD cards with a capacity up to 400 GB (400 billion bytes) are available. The same year, Samsung combined 3D IC chip stacking with its 3D V-NAND and TLC technologies to manufacture its 512GB KLUFG8R1EM flash memory chip with eight stacked 64-layer V-NAND chips. In 2019, Samsung produced a 1TB flash chip, with eight stacked 96-layer V-NAND chips and with QLC technology.
  
  Section::::Principles of operation.
   BULLET::::- Some vendors produced SDSC cards above 1GB before the SDA had standardized a method of doing so.
  
  Section::::Markets.
  
  Secure Digital cards are used in many consumer electronic devices, and have become a widespread means of storing several gigabytes of data in a small size. Devices in which the user may remove and replace cards often, such as digital cameras, camcorders, and video game consoles, tend to use full-sized cards. Devices in which small size is paramount, such as mobile phones, tend to use microSD cards.
   Each NOR flash cell is larger than a NAND flash cell 10 F vs 4 F even when using exactly the same semiconductor device fabrication and so each transistor, contact, etc. is exactly the same size because NOR flash cells require a separate metal contact for each cell.
   The concept is the bulk storing of data optically in non-photosensitive transparent materials such as fused quartz, which is renowned for its high chemical stability and resistance. Writing into it using a femtosecond-laser was first proposed and demonstrated in 1996. The storage media consists of fused quartz where the spatial dimensions, intensity, polarization, and wavelength is used to modulate data. By introducing gold or silver nanoparticles embedded in the material, their plasmonic properties can be exploited.
   Although the effect on performance is most obvious on rotating media, similar effects come into play even for solid-state media like Flash RAM or DRAM. In this case the performance is generally defined by the time it takes for the electrical signals to travel though the computer bus to the chips, and then through the chips to the individual "cells" used to store data (each cell holds one bit).
   Section::::Inconsistent use of units.:Legal disputes.
  
  The different interpretations of disk size prefixes has led to three significant class action lawsuits against digital storage manufacturers.
  
  One case involved flash memory and the other two involved hard disk drives.
  
  Two of these were settled with the manufacturers admitting no wrongdoing but agreeing to clarify the storage capacity of their products on the consumer packaging.
  
  Flash memory and hard disk manufacturers now have disclaimers on their packaging and web sites clarifying the formatted capacity of the devices
  
  or defining MB as 1 million bytes and 1 GB as 1 billion bytes.
  
presuppositions: Small microSD cards are too small to be able to hold 1TB of data.
corrections: Transistors which are inside of Micro SD cards are only 20 nanometers which is significantly smaller than human hair, a transistor that holds 1TB is typically only around 5nm.
raw_presuppositions: Small microSD cards are too small to be able to hold 1TB of data. Small microSD card should not be able to store that much data.
raw_corrections: Transistors which are inside of Micro SD cards are only 20 nanometers which is significantly smaller than human hair, a transistor that holds 1TB is typically only around 5nm. Technology has gotten so good that transistors have been shrunken down so small that this is now possible. 