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Edison cylinder phonograph c. 1899. The phonograph cylinder is a storage medium. The phonograph may be considered a storage device especially as machines of this vintage were able to record on blank cylinders.
On a reel-to-reel tape recorder (Sony TC-630), the recorder is data storage equipment and the magnetic tape is a data storage medium.
Various electronic storage devices, with a coin for scale
DNA and RNA can be considered as biological storage media.[1]
Computer memory and data storage types
General
Volatile
RAM
Historical
Non-volatile
ROM
NVRAM
Early-stage NVRAM
Analog recording
Optical
In development
Historical

Data storage is the recording (storing) of information (data) in a storage medium. Handwriting, phonographic recording, magnetic tape, and optical discs are all examples of storage media. Biological molecules such as RNA and DNA are considered by some as data storage.[1][2] Recording may be accomplished with virtually any form of energy. Electronic data storage requires electrical power to store and retrieve data.

Data storage in a digital, machine-readable medium is sometimes called digital data. Computer data storage is one of the core functions of a general-purpose computer. Electronic documents can be stored in much less space than paper documents.[3] Barcodes and magnetic ink character recognition (MICR) are two ways of recording machine-readable data on paper.

Recording media

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A recording medium is a physical material that holds information. Newly created information is distributed and can be stored in four storage media–print, film, magnetic, and optical–and seen or heard in four information flows–telephone, radio and TV, and the Internet[4] as well as being observed directly. Digital information is stored on electronic media in many different recording formats.

With electronic media, the data and the recording media are sometimes referred to as "software" despite the more common use of the word to describe computer software. With (traditional art) static media, art materials such as crayons may be considered both equipment and medium as the wax, charcoal or chalk material from the equipment becomes part of the surface of the medium.

Some recording media may be temporary, either by design or by nature. Volatile organic compounds may be used to preserve the environment or to purposely make data expire over time. Data such as smoke signals or skywriting are temporary by nature. Depending on the volatility, a gas (e.g. atmosphere, smoke) or a liquid surface such as a lake would be considered a temporary recording medium if at all.

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A 2003 UC Berkeley report estimated that about five exabytes of new information were produced in 2002 and that 92% of this data was stored on hard disk drives. This was about twice the data produced in 2000.[5] The amount of data transmitted over telecommunications systems in 2002 was nearly 18 exabytes—three and a half times more than was recorded on non-volatile storage. Telephone calls constituted 98% of the telecommunicated information in 2002. The researchers' highest estimate for the growth rate of newly stored information (uncompressed) was more than 30% per year.

In a more limited study, the International Data Corporation estimated that the total amount of digital data in 2007 was 281 exabytes and that the total amount of digital data produced exceeded the global storage capacity for the first time.[6]

A 2011 Science Magazine article estimated that the year 2002 was the beginning of the digital age for information storage: an age in which more information is stored on digital storage devices than on analog storage devices.[7] In 1986, approximately 1% of the world's capacity to store information was in digital format; this grew to 3% by 1993, to 25% by 2000, and to 97% by 2007. These figures correspond to less than three compressed exabytes in 1986, and 295 compressed exabytes in 2007.[7] The quantity of digital storage doubled roughly every three years.[8]

It is estimated that around 120 zettabytes of data will be generated in 2023, an increase of 60x from 2010, and that it will increase to 181 zettabytes generated in 2025.[9]

Mass storage

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This section is an excerpt from Mass storage.[edit]

In computing, mass storage refers to the storage of large amounts of data in a persisting and machine-readable fashion. In general, the term mass in mass storage is used to mean large in relation to contemporaneous hard disk drives, but it has also been used to mean large relative to the size of primary memory as for example with floppy disks on personal computers.

Devices and/or systems that have been described as mass storage include tape libraries, RAID systems, and a variety of computer drives such as hard disk drives (HDDs), magnetic tape drives, magneto-optical disc drives, optical disc drives, memory cards, and solid-state drives (SSDs). It also includes experimental forms like holographic memory. Mass storage includes devices with removable and non-removable media.[10][11] It does not include random access memory (RAM).

There are two broad classes of mass storage: local data in devices such as smartphones or computers, and enterprise servers and data centers for the cloud. For local storage, SSDs are on the way to replacing HDDs. Considering the mobile segment from phones to notebooks, the majority of systems today is based on NAND Flash. As for Enterprise and data centers, storage tiers have established using a mix of SSD and HDD.[12]

See also

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References

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Further reading

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Revisions and contributorsEdit on WikipediaRead on Wikipedia

Data storage

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Data storage is the process of recording, preserving, and retrieving digital information using magnetic, optical, mechanical, or within systems, enabling devices to retain for immediate access or long-term archival purposes. This foundational element of supports everything from personal to enterprise-scale operations by converting into physical or virtual representations that can be accessed, modified, or shared as needed. In architectures, data storage is categorized into primary and secondary types, with primary storage—such as random access memory ()—providing volatile, high-speed access for active processing, while secondary storage offers non-volatile, persistent retention for larger volumes of data. Secondary storage devices include hard disk drives (HDDs) that use magnetic media to store data on spinning platters, solid-state drives (SSDs) employing for faster, more reliable performance without moving parts, and optical media like CDs and DVDs that encode information via laser-etched pits and lands. Key characteristics of storage systems encompass capacity (measured in gigabytes or terabytes), access speed (data transfer rates in megabytes per second), durability (resistance to physical degradation), dependability (, or MTBF), and cost-effectiveness (price per unit of storage). Storage can be implemented through (DAS), where devices like HDDs or SSDs connect locally to a single computer, or network-based solutions such as (NAS) for shared file-level access across a local network and storage area networks (SAN) for high-performance block-level data handling in enterprise environments. Advanced storage paradigms include software-defined storage (SDS), which abstracts storage management from hardware to enable scalable, flexible deployment across hybrid infrastructures, and , where data is hosted remotely by providers like or , offering on-demand scalability, redundancy through replication, and global accessibility via the . These advancements address the exponential growth in data volumes driven by , , and the , ensuring reliable preservation and efficient utilization of digital assets.

Fundamentals of Data Storage

Definition and Importance

Data storage refers to the recording and preservation of information in a stable medium, encompassing both analog and digital forms. In analog storage, data is represented continuously, as seen in methods like handwriting on paper or phonographic records that capture sound waves mechanically. Digital storage, on the other hand, encodes information in discrete binary bits (0s and 1s) using technologies such as magnetic, optical, or solid-state media to ensure reliable retention for future access. This dual nature allows for the persistent archiving of diverse data types, from physical artifacts to electronic files. The importance of data storage lies in its role as the foundation of operations, enabling the temporary or permanent retention of essential for running programs and retrieving efficiently. It distinguishes between volatile storage, which requires continuous power to maintain (e.g., RAM that loses content upon shutdown), and non-volatile storage, which retains without power (e.g., hard disk drives). Key metrics include storage capacity, measured in units from bytes to terabytes (TB) or zettabytes (ZB) for large-scale systems, and access speed, which determines how quickly can be read or written, directly impacting system performance. Beyond , data storage underpins modern by ensuring the persistence of , supporting in scientific research through organized that allows verification of results, and enabling scalability by allowing organizations to expand storage in response to growing data needs. It powers industries such as , , and analytics, where reliable storage facilitates complex processing and decision-making. Economically, the global data storage market is expected to reach $484 billion by 2030, driven by surging demands from AI and digital expansion. Without effective data storage, critical digital ecosystems like the and smartphones would be impossible, as they rely on persistent data access for functionality.

Principles of Data Encoding

Digital data storage fundamentally relies on the , where all information is represented as sequences of bits—individual binary digits that are either 0 or 1. These bits encode the basic building blocks of data, such as text, images, and instructions, by leveraging the two-state nature of electronic or physical phenomena in storage media. A byte, the standard unit for data storage, comprises 8 bits, allowing for 256 possible combinations (2^8). Larger units build hierarchically from this foundation: a equals 1,024 bytes (2^10), a 1,024 kilobytes (2^20 bytes), and so on, up to exabytes and beyond, enabling scalable representation of vast datasets. Encoding methods transform abstract data into binary form suitable for storage. For text, the American Standard Code for Information Interchange (ASCII) assigns 7-bit codes to represent 128 characters, primarily English letters, digits, and symbols, with an 8th bit often used for parity or extension. Unicode extends this capability globally, using variable-length encodings like to support over 159,000 characters across scripts, ensuring compatibility with ASCII for legacy systems while accommodating multilingual data. content, such as audio or video, undergoes binary-to-analog conversion during playback; for instance, (PCM) samples analog signals at regular intervals, quantizes them to binary values, and stores them as bit streams, with common rates like 44.1 kHz for CD-quality audio. To maintain integrity, codes are integral: simple parity bits detect single-bit errors by adding a check bit for even or odd parity across data bits, while advanced schemes like Hamming codes enable correction. In Hamming codes, the minimum dd between codewords satisfies d=2t+1d = 2t + 1, allowing correction of up to tt errors per block, as derived from the sphere-packing bound in . At the physical level, storage principles map binary states to tangible properties of media. In , a bit is encoded via magnetization direction—north-south orientation for 1, south-north for 0—achieved by aligning magnetic domains on coated surfaces. Semiconductor-based storage, such as in , represents bits through charge levels: presence or absence of electrons in a floating gate or trap structure denotes 1 or 0, with multi-level cells using varying charge densities for multiple bits per cell. Storage density, quantified as areal density in bits per square inch, drives capacity; modern hard drives achieve over 1 terabit per square inch by shrinking bit sizes and . Reliability is assessed via (BER), the probability of bit flips due to or wear, typically targeted below 10^{-15} for uncorrectable errors in enterprise storage, with error-correcting codes mitigating raw BERs around 10^{-3} in NAND flash. To enhance , introduces duplicate or derived data, allowing reconstruction after failures without loss. Principles underlying systems like employ (duplicating data across units for immediate recovery) or parity (storing XOR checksums to regenerate lost bits), balancing overhead against protection levels. Atomicity ensures storage operations are indivisible: a write either completes fully or not at all, preventing partial updates; for example, disk sectors are designed for atomic writes via buffered power reserves, guaranteeing single-block durability even during interruptions.

Historical Evolution

Pre-Digital Methods

Pre-digital methods of data storage relied on to preserve through mechanical, chemical, or manual means, predating electronic and binary encoding. These techniques emerged from the needs of ancient societies to record administrative, legal, and cultural , evolving into more sophisticated analog systems by the that captured sound and images. One of the earliest forms of data storage involved clay tablets inscribed with script by the Sumerians around 3200 BCE, used for accounting, legal contracts, and literary records that could withstand fire when baked. In , scrolls, made from the of the plant, served as a lightweight medium for hieroglyphic and writing from approximately 3000 BCE, enabling the documentation of religious texts, administrative records, and historical narratives. Stone inscriptions, such as those carved into obelisks and steles in Mesopotamian, Egyptian, and Mesoamerican civilizations, provided durable permanence for public decrees, memorials, and astronomical , with examples like the Mayan glyphs enduring for millennia. In the , innovations expanded storage to dynamic forms like sound and automated data. invented the in 1877, using tin-foil-wrapped cylinders to record and reproduce audio through mechanical grooves, marking the first practical device for storing sound waves. Punched cards, initially developed by in 1801 to control loom patterns via holes representing instructions, were adapted in the 1890s by for tabulating machines during the U.S. Census, storing demographic data mechanically for processing. , introduced with rollable celluloid by in 1885, captured visual data through light-sensitive emulsions, revolutionizing the analog storage of images for scientific, artistic, and documentary purposes. Analog media such as , wax cylinders, and disc records formed the backbone of pre-digital storage, each with inherent limitations in durability and capacity. , used for and later from the onward, stored textual and illustrative but was susceptible to decay from moisture, insects, and wear, often requiring protective bindings like those in that held roughly 1 MB of equivalent per . Wax cylinders, employed in Edison's phonographs from the , recorded audio grooves but degraded quickly due to physical fragility and mold growth, limiting playback to dozens of uses. Emile Berliner's gramophone, patented in 1887, used flat discs—precursors to vinyl—for audio storage, offering better but still prone to scratching, warping from heat, and low density compared to later media. Specific events highlighted the practical application of these methods in communication and recording. In the , systems, pioneered by and others, stored transmitted messages on paper tape perforated with dots and dashes, allowing for delayed reading and error correction in early electrical signaling. Early audio storage advanced with the gramophone's introduction in , enabling the commercial recording of music and speech on discs, which facilitated the preservation of performances for the first time in history. These analog techniques laid foundational concepts for data persistence, bridging manual inscription to mechanical reproduction before the shift to digital systems.

Development of Digital Storage

The development of digital storage began in the mid-20th century with the advent of electronic computing, marking a shift from mechanical and analog methods to magnetic and electronic technologies capable of storing reliably. One of the earliest innovations was magnetic drum memory, patented by Austrian Gustav Tauschek in 1932, which used a rotating coated with ferromagnetic material to store data via magnetic patterns read by fixed heads. Although conceptualized in , practical implementations emerged in the late and , serving as secondary storage in early computers due to its non-volatile nature and ability to hold thousands of bits, though access times were limited by drum rotation speeds of around 3,000-5,000 RPM. By the early 1950s, magnetic core memory became a dominant form of primary storage, invented at MIT's Lincoln Laboratory for the Whirlwind computer project and first operational in 1953. This technology employed tiny rings of ferrite material, each representing a single bit, threaded with wires to detect and set magnetic orientations for data retention without power. Core memory offered random access times under 1 microsecond and capacities up to 4 KB per plane, far surpassing vacuum tube-based Williams-Kilburn tubes in reliability and density, and it powered systems like the IBM 701 until the late 1960s. This era also saw the transition from vacuum tube electronics to semiconductors, beginning with transistorized memory circuits in the mid-1950s, which reduced size, power consumption, and heat while enabling denser integration. In the 1950s and 1960s, secondary storage advanced significantly with and disk systems. The , delivered in 1951, introduced the Uniservo tape drive, the first commercial storage for computers, using 1,200-foot (366 m) reels of nickel-plated tape at 120 inches per second (3.0 m/s) to store up to approximately 1.5 MB per reel in serial access mode. This complemented the 1956 , the inaugural commercial , which featured 50 spinning platters storing 5 MB across 24-inch disks, accessed randomly by movable heads at 8.8 KB/s transfer rates. By the 1970s, evolved with the 1971 8-inch , an 80 KB flexible magnetic disk in a protective , initially designed for mainframe diagnostics but soon adopted for transfer and software distribution. The 1980s and early 2000s brought optical and solid-state breakthroughs, driven by semiconductor advancements. and jointly released the (CD) in 1982, an medium using laser-etched pits on a 12-cm disc to hold 650 MB of , revolutionizing audio and data distribution with error-corrected reading at 1.2 Mbps. This was followed by the DVD in 1995, developed by a including and Warner, which increased capacity to 4.7 GB per side through tighter pit spacing and dual-layer options, enabling video storage and replacing tapes. Concurrently, emerged in 1980 from engineer Fujio Masuoka, who conceived electrically erasable variants presented in 1984, allowing block-level rewriting without mechanical parts for non-volatile storage. The first commercial (SSD) arrived in 1991 from SunDisk (now SanDisk), a 20 MB flash-based module in a 2.5-inch form factor priced at $1,000, targeted at mission-critical laptops for shock resistance. Throughout this period, Gordon Moore's 1965 observation—later termed —that density on chips doubles approximately every 18-24 months profoundly influenced storage evolution, enabling exponential increases in areal density from around 1,000–2,000 bits per in 1950s drums to over 50 gigabits per (50 billion bits per ) in early disks and flash cells. This scaling, combined with fabrication advances, reduced costs per bit by factors of thousands, facilitating the proliferation of personal computing and data-intensive applications by the early .

Types of Storage Media

Magnetic Storage Media

Magnetic storage media rely on the of ferromagnetic materials to encode , where is stored by aligning magnetic domains—microscopic regions of uniformly oriented atomic magnetic moments—in specific patterns. These materials, such as (γ-Fe₂O₃) or cobalt-doped alloys, exhibit , allowing stable retention of magnetic states that represent (0 or 1) through parallel or antiparallel orientations relative to a reference direction. The read/write process utilizes electromagnetic heads: writing involves an inductive head generating a localized to flip domain orientations on the medium, while reading detects changes in or resistance via inductive or magnetoresistive sensors, such as tunnel magnetoresistance (TMR) heads that achieve densities exceeding 1 Tb/in² as of 2025. Modern implementations use tunnel magnetoresistance (TMR) heads for higher sensitivity and densities. Key properties of these materials include and , which determine their suitability for data storage. (H_c) is the intensity of the applied required to reduce the material's to zero, typically around 400,000 A/m (5000 Oe) in modern magnetic recording media, ensuring resistance to unintended demagnetization while allowing controlled writing. , the residual at zero applied field, measures the material's ability to retain data post-writing, with typical values of 0.4–0.5 T in modern recording media enabling compact, stable storage. These properties are balanced in semi-hard magnetic materials to optimize against external fields. Common types of magnetic storage media include tapes, disks, and drums, each leveraging these properties for different recording geometries. Magnetic tapes employ linear serpentine recording, where data is written in parallel tracks across the tape width using multiple heads, reversing direction at each end to back, as seen in LTO-9 cartridges supporting up to 18 TB native with 8960 tracks (as of ). Disks come in rigid (hard) forms with granular layers enabling densities over 500 Gb/in² and flexible variants like floppy disks for removable storage. Drums, cylindrical media coated with ferromagnetic particles, use rotating surfaces for , though largely superseded by modern formats. Magnetic storage offers high capacity and cost-effectiveness for bulk , with enterprise disks reaching up to 36 TB per unit as of 2025, providing low cost per terabyte for archival applications. However, it is susceptible to demagnetization from fields exceeding (e.g., >30,000 A/m erases instantly) and physical issues like head crashes from or wear, which cause signal drop-outs and require frequent maintenance. Areal density, the bits stored per , has evolved dramatically, starting at approximately 1 Mbit/in² in the and growing at rates of 39% annually through the , though slowing to 7.6% by 2018. As of 2025, advancements achieve approximately 2 Tb/in², enabling 30–36 TB drives, with projections to 100 TB per unit by 2030. This progress faces the superparamagnetic limit, where destabilize small magnetic grains (~1 Tbit/in² density), causing data loss. (HAMR) addresses this by using a to temporarily heat the medium during writing, reducing to allow stable recording on smaller, high-coercivity grains while cooling preserves the state.

Optical Storage Media

Optical storage media utilize light-based recording techniques on photosensitive materials to store and retrieve , primarily through the creation of microscopic pits and s on a reflective surface. The disc typically consists of a substrate with a thin reflective layer, such as aluminum, where is encoded as a spiral track of pits (depressions) and lands (flat areas). A low-power beam is directed at the track; when it strikes a land, the reflects back to a , registering as a binary 1, whereas pits cause the to scatter or diffract, resulting in minimal reflection and a binary 0. This non-contact reading mechanism ensures that the layer remains untouched during playback, reducing wear from repeated access. The primary types of optical storage media include compact discs (CDs), digital versatile discs (DVDs), and Blu-ray discs, each advancing in capacity through refinements in laser wavelength and track density. CDs, introduced in 1982 by and , offer a standard capacity of 650 MB using a 780 nm near-infrared and a track pitch of 1.6 µm. DVDs, developed in 1995 and released in 1996, achieve 4.7 GB in single-layer format with a 650 nm red and 0.74 µm track pitch, supporting dual-layer configurations up to 8.5 GB. Blu-ray discs, finalized in 2005 and launched in 2006, provide 25 GB for single-layer and up to 50 GB for dual-layer using a 405 nm blue-violet and 0.32 µm track pitch, enabling higher densities for high-definition content. Writable variants, such as and DVD-R, employ organic dye layers that irreversibly change under a higher-power write to mimic pits, while rewritable formats like and DVD-RW use phase-change materials that switch between crystalline (reflective) and amorphous (absorptive) states for multiple erasures. Optical storage media offer advantages in durability for read-only formats, which resist degradation from repeated access and are immune to magnetic interference, making them suitable for long-term archival in environments like libraries. However, limitations include vulnerability to physical damage such as scratches that can obscure readings, limited rewrite cycles in phase-change media (typically 1,000 times), and lower data densities compared to modern alternatives, contributing to their declining use amid the rise of digital streaming services. Despite these challenges, shorter wavelengths enable progressive increases in storage density, with Blu-ray's allowing pits as small as 0.16 µm, far denser than CDs.

Solid-State Storage Media

Solid-state storage media utilize semiconductor-based materials, primarily , to store data through the retention of electrical charges in the absence of mechanical components. These devices rely on technologies that maintain information without continuous , enabling reliable data persistence in compact forms. The core principle involves trapping electrons in isolated structures within transistors, which alters the device's electrical properties to represent binary states. The fundamental mechanism in most employs floating-gate transistors, where data is stored by modulating the of metal-oxide-semiconductor field-effect transistors (MOSFETs). In these cells, electrons are injected onto a floating gate—a conductive layer insulated from the rest of the transistor—via techniques such as channel hot electron injection for programming or Fowler-Nordheim tunneling for erasure. The presence of trapped charge increases the , typically representing a logic '0', while the absence of charge allows normal conduction, representing a '1' (or vice versa, depending on convention). This charge-based storage enables non-volatility, as the electrons remain trapped until intentionally removed. Two primary architectures dominate solid-state flash memory: NOR and NAND. NOR flash connects cells in parallel, facilitating random access and fast read speeds suitable for executing code directly from the memory, akin to executing small programs without loading into RAM. In contrast, NAND flash arranges cells in series, enabling block-based operations that prioritize higher density and faster sequential writes/erases, making it ideal for bulk data storage. NAND's serial structure reduces the number of connections per cell, allowing for smaller cell sizes and greater compared to NOR's parallel layout. Among solid-state types, electrically erasable programmable read-only memory () serves as a foundational technology, permitting byte-level erasure and rewriting through electrical means without ultraviolet exposure, unlike earlier variants. However, modern high-capacity applications predominantly use NAND flash, which evolved from EEPROM principles but optimizes for larger blocks. NAND variants are classified by the number of voltage levels (bits) stored per cell: single-level cells (SLC) store 1 bit for maximum endurance and speed; multi-level cells (MLC) store 2 bits; triple-level cells (TLC) store 3 bits; and quad-level cells (QLC) store 4 bits, achieving progressively higher densities at the expense of performance and reliability. To overcome planar scaling limits, 3D NAND stacks memory cells vertically, with current generations reaching 200 or more layers; by 2025, manufacturers plan deployments of 420–430 layers, further boosting capacity through increased . Solid-state media offer significant advantages, including rapid access times due to the lack of mechanical seek operations—enabling read latencies in microseconds versus milliseconds for disk-based systems—and exceptional resistance to physical shock and vibration, as there are no moving parts to fail. These properties enhance reliability in mobile and embedded applications. However, limitations include a finite number of program/erase (P/E) cycles per cell, typically ranging from 3,000 for TLC to 100,000 for SLC, beyond which charge retention degrades and errors increase. Additionally, solid-state storage remains more expensive per than magnetic alternatives, though costs have declined with scaling. To mitigate endurance constraints, wear-leveling algorithms distribute write operations evenly across cells, preventing premature wear on frequently accessed blocks and extending overall device lifespan by balancing P/E cycles. Advancements in cell size have driven density improvements, with planar NAND feature sizes shrinking from approximately 90 nm in the early 2000s to around 15 nm by the mid-2010s, after which 3D architectures largely supplanted further lateral scaling to avoid interference issues. By 2025, effective cell dimensions in advanced 3D NAND approach 5 nm equivalents through refined and materials, enabling terabit-scale chips while maintaining charge integrity.

Storage Devices and Systems

Primary Storage Devices

Primary storage devices, also known as main memory or , consist of volatile semiconductor-based components that temporarily hold data and instructions actively used by the (CPU) during computation. These devices enable rapid, random access to data, facilitating efficient program execution in the , where instructions and data share the same addressable memory space. (RAM) serves as the core of primary storage, providing high-speed access essential for real-time processing while losing all stored information upon power loss. The two primary types of RAM are Dynamic RAM (DRAM) and Static RAM (SRAM), each suited to different roles within primary storage due to their underlying mechanisms and performance characteristics. DRAM stores each bit of data in a capacitor paired with a , where the presence or absence of charge represents binary states; however, capacitors naturally leak charge, necessitating periodic refresh cycles every 64 milliseconds to restore , as mandated by standards for reliability across all cells. This refresh process, while ensuring , introduces minor overhead but allows DRAM to achieve high density at lower cost, making it ideal for memory in computers and mobile devices. In contrast, SRAM uses flip-flop circuits with 4-6 s per bit to maintain state without refresh, offering faster access but at higher cost and lower density, thus limiting its use to smaller, speed-critical applications.
FeatureDRAMSRAM
Storage MechanismCapacitor-transistor pair per bit; requires refreshTransistor-based flip-flop per bit; no refresh
Access Time~60 ns~10 ns
Density/CostHigh density, low cost (~$6/GB as of late 2025)Low density, high cost (~$5,000/GB)
Power UsageHigher due to refreshLower overall
Primary UseMain system memoryCPU caches
SRAM's speed advantage positions it predominantly in CPU caches, which form a to bridge the performance gap between the processor and main DRAM. Modern CPUs feature multi-level caches: L1 cache, the smallest and fastest at ~1-4 ns access time and 32-64 KB per core, splits into instruction (L1-I) and (L1-D) subsets embedded directly within each core for immediate access; L2 cache, larger at 256 to 1 MB per core with ~4-10 ns latency, serves as a per-core buffer; and L3 cache, shared across cores at 32 MB or more with ~10-30 ns access, acts as a last-level communal pool before resorting to DRAM. These caches exploit locality principles to store frequently accessed , reducing average access times to under 10 ns for most operations and minimizing the von Neumann bottleneck of shuttling between slow main memory and the fast CPU. In contemporary systems as of 2025, primary storage capacities in consumer PCs reach up to 192 GB or more of DRAM, supporting demanding applications like gaming and while adhering to the von Neumann model's unified addressing. Access latencies for cache-integrated primary storage remain below 10 ns, enabling seamless computation at multi-gigahertz clock speeds. The DDR5 standard, introduced in 2020 by , enhances DRAM performance with initial speeds of 4,800 MT/s and scalability to 8,800 MT/s, doubling bandwidth over DDR4 through on-die error correction and improved efficiency. However, in power-constrained mobile devices, DRAM's refresh overhead and high-bandwidth demands pose challenges, often requiring error-correcting code (ECC) variants or low-power optimizations to balance performance with battery life.

Secondary and Mass Storage

Secondary and mass storage encompasses non-volatile devices designed for persistent beyond the immediate runtime needs of primary , enabling the storage of operating systems, applications, files, and large datasets in computing environments. These systems prioritize capacity and over the ultra-low latency of primary storage, supporting everyday access in personal and enterprise settings. Key technologies include hard disk drives (HDDs), solid-state drives (SSDs), and hybrid drives, each offering trade-offs in performance, cost, and reliability. Hard disk drives (HDDs) function as electromechanical storage units that record magnetically on one or more rapidly rotating aluminum platters coated with ferromagnetic material, with read/write heads floating above the surfaces to access concentric tracks. Platters typically spin at speeds ranging from 5,400 to 15,000 (RPM), with enterprise models often operating at 7,200 or 10,000 RPM to balance performance and heat generation. In 2025, maximum HDD capacities have reached 36 TB for enterprise applications, driven by advancements in (HAMR) and (SMR) technologies. Average seek times for HDDs, which measure the time for the read/write head to position over a target track, fall between 5 and 10 milliseconds, reflecting the mechanical nature of the device. Solid-state drives (SSDs), in contrast, employ NAND flash memory cells to store electronically without , connected via high-speed interfaces such as PCIe 4.0/5.0 and NVMe protocols for direct CPU access and low latency. By 2025, consumer SSD capacities commonly extend to 8 TB, while enterprise models commonly reach 15-30 TB or more, with maximum capacities up to 122 TB or higher using QLC NAND and PCIe 5.0 (with previews of PCIe 6.0 for even greater performance). Enterprise SSDs support sequential read/write speeds exceeding 14,000 MB/s and random operations per second () up to 1.6 million for read-intensive workloads. Hybrid drives integrate a small SSD cache (typically 8-32 GB) with a conventional HDD to accelerate access to frequently used , such as files and applications, while leveraging the HDD's larger capacity for bulk storage. Architectural enhancements in secondary and include Redundant Array of Independent Disks () configurations, which aggregate multiple drives to optimize for performance or redundancy. 0 stripes data across drives for enhanced throughput without , ideal for non-critical high-speed tasks; 1 mirrors data identically for single-drive failure protection; 5 distributes parity across three or more drives to tolerate one failure while improving capacity efficiency; and 6 employs dual parity for tolerance of two failures, suitable for larger arrays. Storage controllers, integrated into drives or host systems, manage these arrays and implement error correction mechanisms like error-correcting codes (ECC), which detect and repair bit-level errors in both HDDs and SSDs to maintain over time. For SSDs, advanced ECC such as low-density parity-check (LDPC) codes handles the higher error rates inherent in wear. These storage solutions serve diverse use cases, from personal computers where HDDs or SSDs store user files and software, to servers hosting databases and virtual machines, and data centers managing petabyte-scale repositories for services and . In enterprise environments, the transition from HDD-dominated systems to SSDs has significantly lowered power usage, with SSD adoption reducing overall storage-related by 80-90% due to the absence of mechanical components and efficient idle states. This shift not only cuts operational costs but also supports denser deployments in power-constrained data centers.

Tertiary and Archival Storage

Tertiary storage refers to systems designed for high-capacity, low-cost retention of that is accessed infrequently, serving as an extension beyond secondary storage for long-term preservation. Archival storage, a subset of tertiary, emphasizes and immutability for that must be retained for years or decades, often offline or nearline. Common media include magnetic tapes, such as (LTO) generations, which provide uncompressed capacities up to 30 TB per cartridge in LTO-10 released in 2025, with a November 2025 announcement upgrading the specification to 40 TB native (up to 100 TB compressed) compatible with existing drives and expected availability by 2026. Optical libraries, utilizing Blu-ray or similar discs in robotic systems, offer capacities in the range of hundreds of terabytes per unit with lifespans exceeding 50 years under proper conditions. Cloud-based archival services, like Deep Archive or Cloud Archive Storage, enable scalable, remote retention at costs as low as $0.00099 per GB per month for retrieval-infrequent . Architectures for tertiary and archival storage typically involve automated systems to manage vast volumes efficiently. Tape libraries or robots, such as the Spectra Cube, can scale to over 50 petabytes of native capacity by housing thousands of cartridges in modular frames, with robotic arms handling loading and retrieval. (HSM) software integrates these tiers, automatically migrating data from faster secondary storage to tape or optical based on access patterns, ensuring seamless policy-based archiving. Optical libraries, like Sony's , stack multiple discs in cartridges for petabyte-scale libraries, supporting write-once formats to prevent alterations. These systems are primarily used for backup and , where is mandated for extended periods. For instance, under the EU's (GDPR), organizations must retain certain records for up to 10 years or more, often using (Write Once, Read Many) capabilities in tapes and optical media to ensure immutability against tampering. Magnetic tapes boast a shelf life of 30 years or longer when stored in controlled environments, far outlasting typical hard disk drives. Economically, LTO tape achieves costs around $0.005 per GB, compared to approximately $0.015 per GB for HDDs, making it ideal for petabyte-scale archives. Advancements like IBM's 2020 demonstration of 317 Gb/in² areal density on prototype strontium ferrite tape highlight potential for even higher capacities in .

Global Data Capacity and Growth

The global datasphere, encompassing all data created, captured, replicated, and consumed worldwide, has expanded dramatically in recent decades, driven by the increasing of information and activities. Historical estimates indicate that the total volume of was approximately 5 exabytes in 2002, a figure that underscores the nascent scale of digital storage at the turn of the . By 2023, this had surged to around 129 zettabytes of data created annually, reflecting a of approximately 23% over the preceding years. Projections from the International Data Corporation (IDC) forecast continued rapid expansion, with the global datasphere reaching an estimated 181 zettabytes in 2025. Meanwhile, the installed base of actual stored data is expected to surpass 200 zettabytes by the same year, as not all generated data is retained long-term. Of this vast volume, roughly 80% consists of , such as videos, social media posts, and sensor outputs, which poses unique challenges for management and analysis. This growth is primarily fueled by the explosion of (IoT) devices—estimated at 21.1 billion connected units globally in 2025—alongside the proliferation of platforms and high-bandwidth video streaming services that generate petabytes of content daily. The infrastructure supporting this growth, particularly data centers, is energy-intensive; by 2025, data storage and processing are anticipated to account for about 2% of global consumption, equivalent to roughly 500 terawatt-hours annually. These trends emphasize the need for efficient storage solutions to sustain the datasphere's trajectory without overwhelming resources.

Digitization and Technological Advancements

Digitization involves converting analog media, such as paper documents, , or vinyl records, into digital formats through processes like scanning or analog-to-digital conversion, enabling binary representation for computer and storage. This shift preserves information without physical degradation and facilitates long-term . Key benefits of digitization include improved searchability, as digital files can be indexed, tagged, and retrieved via text-based queries, and enhanced sharing capabilities across networks without quality loss over time. Compression algorithms amplify these advantages by reducing file sizes: the standard for images employs to achieve compression ratios up to 10:1 while preserving visual fidelity for most applications, significantly lowering storage requirements. Similarly, the MP3 algorithm for audio uses perceptual coding to discard inaudible frequencies, enabling file size reductions of 10-12 times compared to uncompressed formats, making music libraries more manageable. From the 2010s to 2025, hardware advancements have driven storage efficiency, with solid-state drives (SSDs) achieving widespread proliferation in laptops and desktops due to their superior speed and durability over mechanical hard disk drives (HDDs); by 2025, the client SSD market has expanded rapidly, underscoring near-universal adoption in new consumer devices. Innovations in NAND flash technology, such as 3D stacking, have boosted capacity, exemplified by SK Hynix's 321-layer QLC NAND, which began mass production in 2025 and delivers higher bit density per chip. For HDDs, (SMR) overlaps tracks to increase areal density by up to 25%, allowing higher-capacity drives without proportional size increases. Software optimizations have further enhanced efficiency, with identifying and eliminating redundant blocks to reclaim , often combined with compression to achieve average reductions of around 50% in storage footprint for typical workloads. NVMe over Fabrics extends the low-latency benefits of NVMe SSDs to networked environments, supporting high-throughput data access over Ethernet or fabrics in data centers. Cloud platforms like AWS S3 exemplify scaled digitization, handling exabyte-level with automatic scaling and exceeding 99.999999999%. Hybrid storage systems integrate SSD caching layers with HDD bulk storage to optimize performance for frequently accessed data while minimizing costs for archival volumes.

Emerging Technologies and Challenges

One of the most promising emerging technologies in data storage is DNA-based storage, which leverages synthetic DNA molecules to encode digital information with extraordinary density. Theoretical limits allow for up to 1 exabyte of data per gram of DNA, far surpassing traditional media due to the compact structure of genetic code. Microsoft Research has advanced this through prototypes, including a 2019 fully automated system for encoding and retrieving data like short messages in DNA, with ongoing efforts to scale for archival applications. Read and write costs, initially exceeding $1 million per megabyte in early experiments, are projected to drop significantly to around $100 per gigabyte by 2030, driven by improvements in synthesis and sequencing technologies. Holographic storage represents another breakthrough, using interference patterns to store in three-dimensional volumes rather than surface layers. Recent experiments with iron-doped crystals have achieved raw densities of 16.8 gigabytes per cubic centimeter, with practical net densities reaching 9.6 gigabytes per cubic centimeter across multiplexed pages. These advancements, including for and refined erasure models, enable up to 3.4 times more read cycles before refresh, positioning holographic media as a candidate for high-capacity, energy-efficient . Quantum storage, utilizing spin qubits in materials like , promises ultra-fast, secure at quantum scales but faces significant hurdles from decoherence. Systems based on silicon spin qubits in quantum dots have demonstrated phase-flip error correction in three-qubit codes, protecting encoded states against with gate fidelities around 96%. However, physical qubit error rates hover near 10^{-3} per operation, necessitating advanced to achieve reliable, scalable storage for processing. Key challenges in these technologies include and threats. Advanced Encryption Standard-256 (AES-256), a symmetric approved by NIST, remains the gold standard for encrypting stored , supporting 256-bit keys to protect against brute-force attacks in cloud and archival systems. For resilience, immutable storage—enforcing write-once-read-many (WORM) policies via object locks—prevents attackers from altering or deleting backups, as recommended by the (CISA) for critical resources like object and file storage. Sustainability poses another pressing concern, with global data volumes projected to reach approximately 500 zettabytes by 2030, amplifying energy demands and . Data centers alone could generate up to 5 million tons of e-waste annually by 2030 due to rapid hardware turnover from AI and edge deployments. for storage infrastructure is expected to rise moderately, with efficiency gains offsetting some growth, but national projections like Denmark's sixfold increase to 15% of use by 2030 highlight the need for greener alternatives. AI integration is addressing these demands through and automated tiering, optimizing storage by forecasting access patterns and dynamically migrating data across tiers. For instance, Intelligent-Tiering uses to automatically shift infrequently accessed objects to lower-cost storage without performance impact, reducing expenses for AI workloads. In , 5G networks drive the proliferation of micro data centers, which provide localized storage to handle low-latency IoT data processing and support billions of connected devices. These compact facilities, often integrated with network infrastructure, enable scalable, resilient storage at the network edge.

References

  1. https://www.ibm.com/think/topics/data-storage
  2. https://www.redhat.com/en/topics/data-storage
  3. https://www.purestorage.com/knowledge/what-is-data-storage.html
  4. https://home.adelphi.edu/~siegfried/cs170/170l5.pdf
  5. https://www.mordorintelligence.com/industry-reports/data-storage-market
  6. https://web.stanford.edu/class/cs101/bits-bytes.html
  7. https://www.unicode.org/versions/Unicode17.0.0/
  8. https://livecode.byu.edu/unicode/encoding.php
  9. https://ccrma.stanford.edu/courses/192b/Digital_Audio_Systems.pdf
  10. https://users.math.msu.edu/users/jhall/classes/codenotes/hamming.pdf
  11. https://www.cs.uic.edu/~jbell/CourseNotes/OperatingSystems/10_MassStorage.html
  12. https://cseweb.ucsd.edu/classes/fa11/cse240A-a/Slides1/02_Technology-2.pdf
  13. http://ece-research.unm.edu/jimp/611/slides/chap6_1.html
  14. https://pages.cs.wisc.edu/~remzi/Classes/739/Fall2016/Papers/fast16-schroeder.pdf
  15. https://www.pdl.cmu.edu/PDL-FTP/RAID/computin.pdf
  16. https://ocw.mit.edu/courses/6-826-principles-of-computer-systems-spring-2002/d616f25b9394550cfe6a25ecca009649_7.pdf
  17. https://sites.utexas.edu/dsb/tokens/the-evolution-of-writing/
  18. https://scomot.com/how-did-the-ancient-egyptians-retain-their-records/
  19. https://faircompanies.com/articles/unofficial-history-of-databases-from-tally-sticks-to-passports/
  20. https://www.loc.gov/collections/edison-company-motion-pictures-and-sound-recordings/articles-and-essays/history-of-edison-sound-recordings/history-of-the-cylinder-phonograph/
  21. https://www.computerhistory.org/storageengine/punched-cards-control-jacquard-loom/
  22. https://www.capture.com/blogs/insights/evolution-of-the-camera
  23. https://jetstor.com/news/brief-history-data-storage
  24. https://cylinders.library.ucsb.edu/history.php
  25. https://www.loc.gov/collections/emile-berliner/articles-and-essays/gramophone/
  26. https://www.ricomputermuseum.org/data-storage/paper-tape
  27. https://www.ibm.com/history/punched-card-tabulator
  28. https://www.computerhistory.org/storageengine/tauschek-patents-magnetic-drum-storage/
  29. https://www.computerhistory.org/revolution/memory-storage/8/252
  30. https://www.computerhistory.org/storageengine/whirlwind-computer-debuts-core-memory/
  31. https://nationalmaglab.org/magnet-academy/watch-play/interactive-tutorials/magnetic-core-memory/
  32. https://www.computerhistory.org/siliconengine/timeline/
  33. https://www.computerhistory.org/storageengine/tape-unit-developed-for-data-storage/
  34. https://www.ricomputermuseum.org/collections-gallery/interesting_computer_items/univac-magnetic-tape
  35. https://www.ibm.com/history/ramac
  36. https://www.computerhistory.org/storageengine/floppy-disk-loads-mainframe-computer-data/
  37. https://www.reliableplant.com/Read/7895/history-on-this-day-in-1982%2C-compact-disc-was-born
  38. https://www.homemediamagazine.com/consumer-electronics/history-dvd-disc-changed-home-entertainment-39791
  39. https://historyofinformation.com/detail.php?entryid=2330
  40. https://www.computerhistory.org/storageengine/solid-state-drive-module-demonstrated/
  41. https://ourworldindata.org/moores-law
  42. https://www.sciencedirect.com/topics/engineering/magnetic-storage
  43. https://www.sciencedirect.com/science/article/abs/pii/S0304885323001956
  44. https://www.bitraser.com/article/what-is-degaussing.php
  45. https://pubs.aip.org/aip/jap/article/102/1/011301/401291/Perpendicular-recording-media-for-hard-disk-drives
  46. https://www.ultrium.com/lto9.html
  47. https://www.sciencedirect.com/topics/computer-science/magnetic-tape
  48. https://investors.seagate.com/news/news-details/2025/Seagate-Introduces-Hard-Drive-Capacities-of-Up-to-36TB-Extending-Its-HAMR-Based-Mozaic-3-Technology-Platform/default.aspx
  49. https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nbsspecialpublication500-101.pdf
  50. https://nap.nationalacademies.org/read/27445/chapter/3
  51. https://trak.in/stories/60tb-hard-disk-can-be-launched-in-2028-as-hdd-storage-double-in-4-years/
  52. https://ieeexplore.ieee.org/document/6656471/
  53. https://volga.eng.yale.edu/teaching-resources/cds-and-dvds/methods-and-materials
  54. https://www.alaska.edu/controller/projects/document-imaging/background_standards_storage_media.pdf
  55. https://micro.magnet.fsu.edu/electromag/computers/digitalvideodiscs/dvd.html
  56. https://www.sony.com/en/SonyInfo/CorporateInfo/History/SonyHistory/2-09.html
  57. https://www.sony.com/electronics/support/res/manuals/W000/W0002784M.pdf
  58. https://www.sony.com/electronics/support/articles/00029645
  59. https://volga.eng.yale.edu/teaching-resources/cds-and-dvds/application
  60. https://www.loc.gov/preservation/scientists/projects/cd-r_dvd-r_rw_longevity.html
  61. https://www.nps.gov/museum/publications/conserveogram/22-05.pdf
  62. https://files.commons.gc.cuny.edu/wp-content/blogs.dir/26920/files/2024/09/S10_Tsou-Vallier.pdf
  63. https://ieeexplore.ieee.org/document/1199079
  64. https://ieeexplore.ieee.org/document/7553566/
  65. https://www.embedded.com/flash-101-nand-flash-vs-nor-flash/
  66. https://resources.system-analysis.cadence.com/blog/nand-vs-nor-flash-memory-for-embedded-systems
  67. https://en.giantec-semi.com/blog/what-is-eeprom-vs-flash-understanding-the-key-differences
  68. https://semiconductor.samsung.com/support/tools-resources/dictionary/semiconductors-101-part-2-different-types-of-nand-flash/
  69. https://www.tomshardware.com/pc-components/storage/inside-the-future-of-3d-nand-the-roadmap-to-500-layers
  70. https://www.techtarget.com/searchstorage/tip/The-pros-and-cons-of-flash-memory-revealed
  71. https://www.wwt.com/article/understanding-nand-flash-memory-in-ssds-types-challenges-and-advancements
  72. https://ieeexplore.ieee.org/document/9265320
  73. https://diveintosystems.cs.swarthmore.edu/book/C5-Arch/von.html
  74. https://www.enterprisestorageforum.com/hardware/sram-vs-dram/
  75. https://istc-cc.cmu.edu/publications/papers/2015/avatar-dram-refresh_dsn15.pdf
  76. https://www.howtogeek.com/891526/l1-vs-l2-vs-l3-cache/
  77. https://www.intel.com/content/www/us/en/developer/articles/technical/memory-performance-in-a-nutshell.html
  78. https://avadirect.com/blog/understanding-computer-ram-how-much-do-you-need-in-2025-when-building-a-custom-pc/
  79. https://www.crucial.com/articles/about-memory/everything-about-ddr5-ram
  80. https://www.micron.com/about/blog/memory/dram/advantage-of-error-correcting-code-ecc-dram-in-smartphones
  81. https://www.ibm.com/think/topics/primary-vs-secondary-storage
  82. https://www.geeksforgeeks.org/computer-organization-architecture/hard-disk-drive-hdd-secondary-memory/
  83. https://www.techradar.com/best/large-hard-drives-and-ssds
  84. https://semiconductor.samsung.com/consumer-storage/internal-ssd/990-pro/
  85. https://semiconductor.samsung.com/consumer-storage/internal-ssd/9100-pro/
  86. https://www.techtarget.com/searchstorage/definition/hybrid-hard-drive
  87. https://www.dell.com/support/kbdoc/en-us/000128635/dell-servers-what-are-the-raid-levels-and-their-specifications
  88. https://www.kingston.com/en/ssd/data-protection
  89. https://sabrent.com/blogs/storage/error-correction-ecc
  90. https://www.trendforce.com/news/2024/04/12/news-ssd-vs-hdd-battle-gets-underway-again/
  91. https://phisonblog.com/3-ways-ssds-help-reduce-data-center-costs/
  92. https://www.enterprisestorageforum.com/news/2002-worst-year-in-the-history-of-it-idc/
  93. https://aws.amazon.com/blogs/publicsector/aws-partners-help-public-sector-organizations-harness-the-power-of-data/
  94. https://www.red-gate.com/blog/database-development/whats-the-real-story-behind-the-explosive-growth-of-data
  95. https://rivery.io/blog/big-data-statistics-how-much-data-is-there-in-the-world/
  96. https://cybersecurityventures.com/the-world-will-store-200-zettabytes-of-data-by-2025/
  97. https://www.forbes.com/councils/forbestechcouncil/2022/02/03/the-unseen-data-conundrum/
  98. https://iot-analytics.com/number-connected-iot-devices/
  99. https://solartechonline.com/blog/how-much-electricity-data-center-use-guide/
  100. https://www.pfu-us.ricoh.com/blog/what-is-digitization
  101. https://solutionshub.epam.com/blog/post/digitization-vs-digitalization
  102. https://cs.stanford.edu/people/eroberts/courses/soco/projects/data-compression/lossy/jpeg/index.htm
  103. https://cs.stanford.edu/people/eroberts/courses/soco/projects/data-compression/lossy/mp3/index.htm
  104. https://www.technavio.com/report/client-solid-state-drive-ssd-market-industry-analysis
  105. https://news.skhynix.com/sk-hynix-begins-mass-production-of-321-layer-qlc-nand-flash/
  106. https://investors.seagate.com/news/news-details/2013/Seagate-Delivers-On-Technology-Milestone-First-To-Ship-Hard-Drives-Using-Next-Generation-Shingled-Magnetic-Recording/default.aspx
  107. https://www.bdrshield.com/vmware-backup/data-compression-and-deduplication/
  108. https://www.starwindsoftware.com/blog/what-is-nvme-of-nvme-over-fabrics/
  109. https://aws.amazon.com/s3/
  110. https://arstechnica.com/information-technology/2016/04/microsoft-experiments-with-dna-storage-1000000000-tb-in-a-gram/
  111. https://news.microsoft.com/source/features/innovation/hello-data-dna-storage/
  112. https://pmc.ncbi.nlm.nih.gov/articles/PMC11189537/
  113. https://www.nature.com/articles/s41586-022-04986-6
  114. https://physics.aps.org/articles/v17/176
  115. https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.197-upd1.pdf
  116. https://www.cisa.gov/stopransomware/ransomware-guide
  117. https://www.ehn.org/ai-data-center-energy-use
  118. https://www.iea.org/energy-system/buildings/data-centres-and-data-transmission-networks
  119. https://aws.amazon.com/s3/storage-classes/intelligent-tiering/
  120. https://blog.se.com/datacenter/edge-computing/2024/08/25/micro-data-centers-evolve-to-fit-new-business-requirements-of-edge-computing/
  121. https://www.extremenetworks.com/resources/solution-brief/5g-driving-multi-access-edge-micro-data-centers
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