Last week had 220 HDDs versus a 3.2803-year normal of 23.280 HDDs, Refinitiv data showed.
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It makes HDDs twice as fast as they normally are, but it doesn't ax the annoying kathunk sound HDDs make.
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That compared with 187 HDDs in the same week last year and a 30-year normal of 201 HDDs for this time of year.
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The weather was warmer than normal last week with 247 heating degree days (HDDs) versus a 30-year normal of 85 HDDs for the period.
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It projected 218 heating degree days (HDDs) in the time period, lower than the 2101 HDDs estimated on Friday, which is indicative of warming weather.
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Data provider Refinitiv estimated 401 heating degree days (HDDs) in the Lower 48 U.S. states over the next two weeks, down from Thursday's estimate of 411 HDDs.
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There were 114 HDDs in the same week a year ago.
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The NWS projected heating degree days (HDDs) would total 1,569 during in January and February.
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SSDs aren't just incredibly durable compared to hard disk drives (HDDs), they're also a lot faster.
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At the same time, SSD longevity has improved, though they still can't match HDDs for archival purposes.
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MacOS The secure erase options offered for HDDs by macOS' Disk Utility are not available for SSDs.
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HDDs measure the number of degrees a day's average temperature is below 13 degrees Fahrenheit (18 degrees Celsius).
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Best of all it works on HDDs, SSDs, CDs, magnetic tape, people, and portable drives—and it's cross-platform.
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Like with HDDs, this has to be performed from outside the operating system and will be executed by the firmware.
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At the moment, cloud storage providers are using solid state memory, HDDs, and magnetic tape simultaneously to keep up with demand.
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HP is providing single panel access to the HDDs, SSDs, and RAM, making it easy to upgrade all three with just a Philips screwdriver.
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I put Intel's new hardware through a series of benchmarks to test just how much it could improve the performance of HDDs and SSDs.
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That compares with just 1,314 HDDs during the same period in the unusually warm winter of 2017 and a 10-year average of 1,598.
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It also includes a Cortex-A9 processor with 4GB of RAM, and up to two HDDs that support a max of 2TB of storage each.
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When it comes to the solid-state drives that have replaced HDDs in many modern laptops, such as MacBooks and Windows ultrabooks, things get more complicated.
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HDDs measure the number of degrees a day's average temperature is below 65 Fahrenheit (18 Celsius) and are used to estimate demand to heat homes and businesses.
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For heating degree days, or HDDs, based on temperatures below 65 Fahrenheit, the September-December 2015 average was 10, less than the 30-year average of 13.
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MacOS The Disk Utility in macOS (formerly OS X) provides multiple data erasure options for HDDs under "Security Options" including multipass overwrites that conforms to the DoD 250-M specification.
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The per-file sanitization methods that typically work on HDDs and which involve overwriting a file's physical location on disk multiple times with random data proved completely inefficient on SSDs.
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In fact, a 2015 study of several external Western Digital hard disk drives (HDDs) with self-encrypting capabilities found serious implementation flaws that could have allowed attackers to recover data or decryption keys.
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It's surprisingly strong, capable of supporting either a laptop or a computer monitor, and features a secret drawer where you can stash flash drives, external HDDs, memory cards, stationery, and other odds and ends.
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However, we expect HDD sales volumes to be protected in the medium term by the growth in the overall data storage market and a continuing substantial per-gigabyte price differential between SSDs and HDDs.
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They emerged as superior, if more expensive, replacements for the traditional hard disk drives or HDDs—with no moving parts, SSDs represented a leap forward in terms of read and write speeds as well as reliability.
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On Friday, Western Digital announced a potential game changer that promises to expand the limits of traditional HDDs to up to 40TBs using a microwave-based write head, and the company says it will be available to the public in 2019.
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" Alexis Daniel, a spokeswoman for ETP, in an email said "we are working in coordination with FERC on all of the remaining HDDs (horizontal directional drilling)and are in compliance with the HDD contingency plan that was approved by FERC.
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Traditional, mechanical HDDs will usually only slow down noticeably right before giving up on life completely, although it's true that buggy code and power cuts can occasionally cause corruptions that in turn give the OS more work to do and might impact performance.
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As its name suggests, SSD is solid—unlike the traditional mechanical hard disk drives (HDDs) fitted in most desktops and laptops since the dawn of portable computing, which use a read/write head floating over a magnetic platter, there are no moving parts.
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There's support for external USB HDDs, which means regardless of how much internal storage you have on your PS4, you can add up to 8TB of additional space via external drives, ensuring you'll never run out of room for games and saves.
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The company proceeded to guide for an even worse FQ4 as falling revenues are not offset by lower opex," JPMorgan said, adding "we see structural weakness in end-market demand as PCs continue to be weak and flash adoption accelerates at the expense of high-performance HDDs.
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"With topline likely flattish at best, GMs [gross profit margin] heading lower, and worse than expected NAND [flash memory] pricing driving increased potential for cannibalization of HDDs [hard disk drives], we see risk to the downside for Seagate after an excellent run," analyst C.J. Muse said in a note to clients Tuesday.
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By the end of the 80s and beginning/mid of the 90s there weren't 128 GB USB-Sticks, Blu-Rays or 5 TB HDDs and all we had for saving data were floppy disks with 1,44 MB or even less—hard disks were just too expensive and a new thing called 'CD-ROM' was even more expensive.
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But with so many cheaper laptops still offering HDDs and not incorporating USB-C — which looks to be the next major port we'll all be using for the next decade or so — the VivoBook could be a good pickup if you're in the market for a low-cost PC. You can purchase the Asus VivoBook E403SA from Asus' website or on Amazon.
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Third-party tools for executing the ATA Secure Erase command on both HDDs and SSDs include Parted Magic, a previously free bootable CD for partition management that now costs $268 to download, and HDDerase, a bootable DOS-based utility originally developed at the University of California San Diego's Center for Memory and Recording Research, but which hasn't been updated since 27 and might not work with some drives or some configurations.
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SSDs have a higher data transfer rate, lower power consumption, lower failure rate, and a larger capacityBeHardware reported lower retailer return rates for SSDs than HDDs between April and October 2010. A 2011 study by Intel on the use of 45,000 SSDs reported an annualized failure rate of 0.61% for SSDs, compared with 4.85% for HDDs. compared to HDDs. However, HDDs have a significantly lower cost.
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Introduced by IBM in 1956, HDDs were the dominant secondary storage device for general- purpose computers beginning in the early 1960s. HDDs maintained this position into the modern era of servers and personal computers, though personal computing devices produced in large volume, like cell phones and tablets, rely on flash products. More than 224 companies have produced HDDs historically, though after extensive industry consolidation most units are manufactured by Seagate, Toshiba, and Western Digital. HDDs dominate the volume of storage produced (exabytes per year) for servers.
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However, HDDs generally are not wear-leveled devices in the context of this article.
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This section lists IBM manufactured HDDs offered both as an OEM product and for attachment to IBMs small systems such as the System/3, System/32, /34 & /36 and the AS/400. HDDs are identified by their OEM model number and listed chronologically by date of first customer shipment.
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Instead of creating a magnetisation distribution in analog recording, digital recording only needs two stable magnetic states, which are the +Ms and -Ms on the hysteresis loop. Examples of digital recording are floppy disks and hard disk drives (HDDs). Digital recording has also been carried out on tapes. However, HDDs offer superior capacities at reasonable prices; at the time of writing (2020), consumer-grade HDDs offer data storage at about $0.03 per GB. Recording media in HDDs use a stack of thin films to store information and a read/write head to read and write information to and from the media; various developments have been carried out in the area of used materials.
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Because of smaller platter(s), mobile HDDs generally have lower capacity than their desktop counterparts. : There are also 2.5-inch drives spinning at 10,000 rpm, which belong to the enterprise segment with no intention to be used in laptops. ; Enterprise HDDs : Typically used with multiple-user computers running enterprise software.
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These practices were used in both data storage-dedicated (for servers, NASes and cold storage) and consumer-centric HDDs.
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The usage share of HDDs is declining and could drop below 50% in 2018–2019 according to one forecast, because SSDs are replacing smaller-capacity (less than one-terabyte) HDDs in desktop and notebook computers and MP3 players. The market for silicon-based flash memory (NAND) chips, used in SSDs and other applications, is growing faster than for HDDs. Worldwide NAND revenue grew 16% per year from $22 billion to $57 billion during 2011–2017, while production grew 45% per year from 19 exabytes to 175 exabytes.
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Destroyed hard disk, glass platter visible Diagram labeling the major components of a computer HDD Recording of single magnetisations of bits on a 200 MB HDD-platter (recording made visible using CMOS-MagView). Longitudinal recording (standard) & perpendicular recording diagram The platters in contemporary HDDs are spun at speeds varying from 4,200 RPM in energy-efficient portable devices, to 15,000 rpm for high-performance servers. The first HDDs spun at 1,200 rpm and, for many years, 3,600 rpm was the norm. , the platters in most consumer-grade HDDs spin at 5,400 or 7,200 RPM.
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The integrated SAN consists of the HDD module (which accommodates up to fourteen 2.5" HDDs in the MFSYS25 chassis, and up to six 3.5" HDDs in the MFSYS35 chassis) and the Storage Control Module(s). Each Compute Blade accesses volumes, which are assigned to it by connecting to the Storage Control Module(s) through its integrated SAS HBA.
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Using bcache makes it possible to have SSDs as another level of indirection within the data storage access paths, resulting in improved overall performance by using fast flash- based SSDs as caches for slower mechanical hard disk drives (HDDs) with rotational magnetic media. That way, the gap between SSDs and HDDs can be bridged the costly speed of SSDs gets combined with the cheap storage capacity of traditional HDDs. Caching is implemented by using SSDs for storing data associated with performed random reads and random writes, using near-zero seek times as the most prominent feature of SSDs. Sequential I/O is not cached, to avoid rapid SSD cache invalidation on such operations that are already suitable enough for HDDs; going around the cache for big sequential writes is known as the write-around policy.
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HDDs are being superseded by solid-state drives (SSDs) in markets where their higher speed (up to 4950 megabytes per second for M.2 (NGFF) NVME SSDs or 2500 megabytes per second for PCIe expansion card drives), ruggedness, and lower power are more important than price, since the bit cost of SSDs is four to nine times higher than HDDs. , HDDs are reported to have a failure rate of 2–9% per year, while SSDs have fewer failures: 1–3% per year. However, SSDs have more un-correctable data errors than HDDs. SSDs offer larger capacities (up to 100 TB) than the largest HDD and/or higher storage densities (100 TB and 30 TB SSDs are housed in 2.5 inch HDD cases but with the same height as a 3.5-inch HDD), although their cost remains prohibitive. A laboratory demonstration of a 1.33-Tb 3D NAND chip with 96 layers (NAND commonly used in solid state drives (SSDs)) had 5.5 Tbit/in2 , while the maximum areal density for HDDs is 1.5 Tbit/in2.
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The Storage Control Module supports Intel Matrix RAID, and manages the RAID partitioning of the HDDs in the integrated HDD bay; as well as the creation, assignment, replication and destruction of volumes on the HDDs' partitions. The Ethernet Switch Module is a managed Gigabit Ethernet switch that provides the installed Compute Blades with connectivity to each other and to external Ethernet networks.
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Retrieved January 7, 2013. The revenues for SSDs, most of which use NAND, slightly exceed those for HDDs. Flash storage products had more than twice the revenue of hard disk drives . Though SSDs have four to nine times higher cost per bit, they are replacing HDDs in applications where speed, power consumption, small size, high capacity and durability are important.
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The areal density of flash memory is doubling every two years, similar to Moore's law (40% per year) and faster than the 10–20% per year for HDDs. , the maximum capacity was 16 terabytes for an HDD, and 100 terabytes for an SSD. HDDs were used in 70% of the desktop and notebook computers produced in 2016, and SSDs were used in 30%.
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In modern computers, hard disk drives (HDDs) or solid-state drives (SSDs) are usually used as secondary storage. The access time per byte for HDDs or SSDs is typically measured in milliseconds (one thousandth seconds), while the access time per byte for primary storage is measured in nanoseconds (one billionth seconds). Thus, secondary storage is significantly slower than primary storage. Rotating optical storage devices, such as CD and DVD drives, have even longer access times.
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Due to the shift in population in the United States toward the sun belt, summer demand for natural gas is rising faster than winter demand. Temperature effects are measured in terms of 'heating degree days' (HDD) during the winter, and 'cooling degree days' (CDD) during the summer. HDDs are calculated by subtracting the average temperature for a day (in degrees Fahrenheit) from . Thus, if the average temperature for a day is , there are 15 HDDs.
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The Modular Server Chassis comes in two versions; the MFSYS25 and MFSYS35. The key difference between these two versions is that the MFSYS25's integrated hard disk drive (HDD) bay accommodates fourteen 2.5" HDDs, while the MFSYS35's integrated HDD bay accommodates six 3.5" HDDs. Both versions have two Main Fan Modules, six Compute Blade bays, five Service Module slots, and up to four power supply units in an N+1 configuration.
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For some time in the 2000s and early 2010s some desktop users and data centers also used 10k RPM drives such as Western Digital Raptor but such drives have become much rarer and are not commonly used now, having been replaced by NAND flash-based SSDs. ; Mobile (laptop) HDDs : Two enterprise-grade SATA 2.5-inch 10,000 rpm HDDs, factory- mounted in 3.5-inch adapter frames : Smaller than their desktop and enterprise counterparts, they tend to be slower and have lower capacity. Mobile HDDs spin at 4,200 rpm, 5,200 rpm, 5,400 rpm, or 7,200 rpm, with 5,400 rpm being the most common. 7,200 rpm drives tend to be more expensive and have smaller capacities, while 4,200 rpm models usually have very high storage capacities.
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Figure 1: Disk structures: In computer disk storage, a sector is a subdivision of a track on a magnetic disk or optical disc. Each sector stores a fixed amount of user-accessible data, traditionally 512 bytes for hard disk drives (HDDs) and 2048 bytes for CD-ROMs and DVD-ROMs. Newer HDDs use 4096-byte (4 KiB) sectors, which are known as the Advanced Format (AF). The sector is the minimum storage unit of a hard drive.
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2.5-inch HDDs are more compact, power efficient, and produce less heat, while at the same time have a smaller capacity and a slower data transfer rate. Some very compact laptops support even smaller 1.8-inch HDDs. For SSDs, however, these miniaturization- related trade-offs are nonexistent, because SSDs were designed to have a very small footprint. SSDs feature a traditional 2.5- or 1.8-inch or a laptop- specific mSATA or M.2 card's form factor.
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Drives running at 10,000 or 15,000 rpm use smaller platters to mitigate increased power requirements (as they have less air drag) and therefore generally have lower capacity than the highest capacity desktop drives. Enterprise HDDs are commonly connected through Serial Attached SCSI (SAS) or Fibre Channel (FC). Some support multiple ports, so they can be connected to a redundant host bus adapter. : Enterprise HDDs can have sector sizes larger than 512 bytes (often 520, 524, 528 or 536 bytes).
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For example, Advanced Format (AF) 512e HDDs use 4096-byte physical sectors, while their firmware provides emulation for a virtual sector size of 512 bytes; thus, "512e" stands for "512-byte emulation".
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The technology is not new, but modern SSD architecture, as well as the availability of powerful embedded processors, make it more appealing to run user applications in-place. SSDs deliver higher data throughput in comparison to hard disk drives (HDDs). Additionally, in contrast to the HDDs, the SSDs can handle multiple I/O commands at the same time. The SSDs contain a considerable amount of processing horsepower for managing flash memory array and providing a high-speed interface to host machines.
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Synthetic benchmarks show different levels of performance improvements when multiple HDDs or SSDs are used in a RAID 0 setup, compared with single-drive performance. However, some synthetic benchmarks also show a drop in performance for the same comparison.
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A Dell PowerEdge RAID Controller, or Dell PERC, is a series of RAID, disk array controllers made by Dell for its PowerEdge server computers. The controllers support SAS and SATA hard disk drives (HDDs) and solid-state drives (SSDs).
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It is one of Funeral For A Friend's most popular songs to date. It was featured in the soundtrack for Madden NFL 06. The song was also included as pre-installed music on the HDDs of the early Xbox 360s.
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There is no known OEM version of this HDD. # 9336 Disk Unit used the IBM 0681 HDD (Redwing)1993 Disk/Trend Report – Rigid Disk Drives, p. RESPEC-61 # 9337 Disk Array Subsystem used the IBM 0662 (Spitfire) or 0663 (Corsair) HDDs.
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A hybrid array is a form of hierarchical storage management that combines hard disk drives (HDDs) with solid-state drives (SSDs) for I/O speed improvements. Hybrid storage arrays aim to mitigate the ever increasing price-performance gap between HDDs and DRAM by adding a non-volatile flash level to the memory hierarchy. Hybrid arrays thus aim to lower the cost per I/O, compared to using only SSDs for storage. Hybrid architectures can be as simple as involving a single SSD cache for desktop or laptop computers, or can be more complex as configurations for data centers and cloud computing.
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In October 1991 the 9345 DASD was announced as part of the IBM 9340 channel-attached, count key data (CKD) DASD subsystem family which attached to IBM mainframes including the ES/9000 processor family.9340 DASD Subsystem Family of Products, IBM Service For Consultants Manual, Oct 1991, p. M9340 The 9345 DASD Model 1 had two 1.0 GB HDDs while the Model 2 had two 1.5 GB HDDs. For most practical applications, the 9340/9345 was functionally equivalent to a 3990/3390, although without non-volatile RAM cache of the 3990 and with a somewhat shorter maximum block length than the 3390.
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Typical read–write power consumption for the SSD is around 0.3 W, and 0.01 W when idle. The different HDDs are rated at about 1.5–2.5 W for read–write operations and around 0.7 W when idle.Momentus 5400.4 SATA. Product Manual. seagate.
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An unstructured repository may simply be a stack of tapes, DVD-Rs or external HDDs with minimal information about what was backed up and when. This method is the easiest to implement, but unlikely to achieve a high level of recoverability as it lacks automation.
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In April 2008, Seagate was the first to ship 1 billion HDDs. According to CNet, it took 17 years to ship the first 100 million and 15 years to ship the next 900 million. In 2009, Bill Watkins was released from employment as CEO.
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Building on the modular expansion capabilities of the compute blade, the storage blade enabled customers to add up to eight 2.5" SATA HDDs or four 3.5" SATA HDDs to a separate, but physically connected, single-width blade add-on. This bolted on expansion took the place of the default blade cover and extended the blade unit to a two-width module. From a computational standpoint, the storage blade was no different from the compute blade, offering the same Intel processor options. Unlike the compute blade, PCIe expansion was not available in the storage blade, as the RAID card supporting the additional hard drives occupied this port.
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First implementation of TDMR in a product (2017) In 2017, M. Fatih Erden announced at the TMRC conference that Seagate had been shipping HDDs with TDMR since earlier that year.M. Kief, I. Tagawa, "The 28th Magnetic Recording Conference (TMRC 2017)", IEEE Trans. Magn., Vol. 54, No. 2, Feb.
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Thus, the tracks partially overlap similar to roof shingles. This approach was selected because physical limitations prevent recording magnetic heads from having the same width as reading heads, leaving recording heads wider.K. Shimomura, "Large-Capacity HDDs Applying SMR Technology for Data Centers", Toshiba Technology Review, Vol. 24, No. 6.
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A disassembled and labeled 1997 HDD lying atop a mirror An overview of how HDDs work A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage and one or more rigid rapidly rotating platters coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks of data can be stored and retrieved in any order. HDDs are a type of non-volatile storage, retaining stored data even when powered off.
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0.8 - A patch that fixed GTA: Liberty City Stories and the ability to edit the DMA button configuration. 0.8b - fixes a bug with HDL0.8 not installing to HDDs over 128 GB and a few other minor errors. Updated compatibility menu. 0.8b+ - A patch that fixed God of War II was added.
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Fixed- block architecture was adopted for a few mainframe HDDs produced by IBM beginning in the 1970s, and contemporary DASD systems continue to support 3310 and 3370 compatibility. MVS continues to require CKD DASD, although by the 1990s all new IBM HDDs used fixed sectors internally. IBM's various FBA disks had block sizes of 100IBM 350 disk storage unit or 200 characters, and 270,IBM 2311 Field Engineering Theory of Operation describes the internals of the IBM 2311, which had both a count key data model and two models with fixed-size data blocksIBM System/360 Model 20 Functional Characteristics 366,IBM System/360 model 44 Functional Characteristics 512,IBM 3310 Direct Access Storage Reference Manual 1024, 2048, or 4096 bytes.
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The C/H/S scheme has been replaced by logical block addressing (LBA), a simple linear addressing scheme that locates blocks by an integer index, which starts at LBA 0 for the first block and increments thereafter. When using the C/H/S method to describe modern large drives, the number of heads is often set to 64, although a typical hard disk drive, , has between one and four platters. In modern HDDs, spare capacity for defect management is not included in the published capacity; however, in many early HDDs a certain number of sectors were reserved as spares, thereby reducing the capacity available to the operating system. For RAID subsystems, data integrity and fault-tolerance requirements also reduce the realized capacity.
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In this manner, data can be stored with higher areal-density on the disks thus providing higher capacity in each HDD.A. Shilov speaking with Mark Re, Seagate CTO, "The evolution of hdds in the near future", AnandTech: 6 July, 2016T. Coughlin, "Two-dimensional Magnetic Recording and other HDD news", Forbes: Enterprise Tech., Apr 29, 2018R.
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Such detectors using a soft Viterbi algorithm or BCJR algorithm are essential in iteratively decoding the low-density parity- check code used in modern HDDs. A single integrated circuit contains the entire read and write channels (including the iterative decoder) as well as all the disk control and interface functions. There are currently two suppliers: Broadcom and Marvell.
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The data associated with sequential reads and writes is not cached on SSDs, avoiding undesirable cache invalidation during such operations; performance-wise, this is beneficial because the sequential I/O operations are suitable for HDDs due to their mechanical nature. Not caching the sequential I/O also helps in extending the lifetime of SSDs used as caches.
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Smith sources and distributes active, passive, and electromechanical IC components, as well as computer products and peripherals such as HDDs, processors, memory modules, video cards - both obsolete and in-production parts. It serves customers in a broad range of industries, including consumer electronics, enterprise electronics, server hardware, automotive, telecommunications, medical, oil and gas, energy, and aeronautics and defense.
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Floppy disks are not partitioned; however depending upon the OS they may require volume information in order to be accessed by the OS. Partition editors and ICKDSF today do not handle low level functions for HDDs and optical disc drives such as writing timing marks, and they cannot reinitialize a modern disk that has been degaussed or otherwise lost the factory formatting.
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Enumerating files, and any inode metadata in general, is much slower on APFS when it is located on a hard disk drive. This is because instead of storing metadata at a fixed location like HFS+ does, APFS stores them alongside the actual file data. This fragmentation of metadata means more seeks are performed when listing files, acceptable for SSDs but not HDDs.
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The first 3.5-inch product was the CP340 HDD with a capacity of 20 MBytes. The subsequent HDD, CP341, established the popularity of the ATA interface supplied by Western Digital. By 1990, Conner Peripherals was the fastest growing start-up company in the history of US commerce, beating the competition with HDDs that were lighter, more compact, and consumed less power.
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A block, a contiguous number of bytes, is the minimum unit of storage that is read from and written to a disk by a disk driver. The earliest disk drives had fixed block sizes (e.g. the IBM 350 disk storage unit (of the late 1950s) block size was 100 6 bit characters) but starting with the 1301 IBM marketed subsystems that featured variable block sizes: a particular track could have blocks of different sizes. The disk subsystems and other Direct access storage devices on the IBM System/360 expanded this concept in the form of Count Key Data (CKD) and later Extended Count Key Data (ECKD); however the use of variable block size in HDDs fell out of use in the 1990s; one of the last HDDs to support variable block size was the IBM 3390 Model 9, announced May 1993.
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Also there is confusion regarding storage capacity, since capacities are stated in decimal Gigabytes (powers of 10) by HDD manufacturers, whereas some operating systems report capacities in binary Gibibytes, which results in a smaller number than advertised. Performance is specified by the time required to move the heads to a track or cylinder (average access time) adding the time it takes for the desired sector to move under the head (average latency, which is a function of the physical rotational speed in revolutions per minute), and finally the speed at which the data is transmitted (data rate). The two most common form factors for modern HDDs are 3.5-inch, for desktop computers, and 2.5-inch, primarily for laptops. HDDs are connected to systems by standard interface cables such as PATA (Parallel ATA), SATA (Serial ATA), USB or SAS (Serial Attached SCSI) cables.
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It used the entire space of a 1.2 MB floppy disk. In 1980s, most machines only had two floppy drives because HDDs were an expensive additional feature for PCs. NEC provided a variety of operating systems including the CP/M-86, Concurrent CP/M, MS-DOS, PC-UX, OS/2, and Windows (discontinued after Windows 2000). Localized versions of NetWare and FreeBSD were also available.
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Hardware implements cache as a block of memory for temporary storage of data likely to be used again. Central processing units (CPUs) and hard disk drives (HDDs) frequently use a cache, as do web browsers and web servers. A cache is made up of a pool of entries. Each entry has associated data, which is a copy of the same data in some backing store.
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Kanotix can be installed to the hard disk using the (graphical) acritoxinstaller,acritoxinstaller which, depending on optical drive, hard disk and processor speed, can take around 10–20 minutes. The acritoxinstaller is a KDE/Qt frontend and a bash backend and comes with a user-friendly interface and several advanced features: e.g. LVM support, dmraid support, automatic partitioning (including ntfsresize-support), installation to USB-HDDs.
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Advanced Format (AF) is any disk sector format used to store data on magnetic disks in hard disk drives (HDDs) that exceeds 512, 520, or 528 bytes per sector, such as the 4096, 4112, 4160, and 4224-byte (4 KB) sectors of an Advanced Format Drive (AFD). Larger sectors enable the integration of stronger error correction algorithms to maintain data integrity at higher storage densities.
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It made around US$11 billion worth of investment pledges to the Vietnamese economy in 2014. As technologies evolve, e.g., as HDDs are replaced by solid-state drives (SSDs), manufacturers are reexamining where best to produce these latest technologies. In addition, 74 percent of salaried workers in the sector face a high risk of being replaced by robots, as these positions consist of "repetitive, non-cognitive tasks".
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For the write-through policy, which ensures that no write operation is marked as finished until the data requested to be written has reached both SSDs and HDDs, performance improvements are reduced by effectively performing only caching of the written data. Write-back policy with batched writes to HDDs provides additional benefits to write-sensitive redundant array of independent disks (RAID) layouts such as RAID 5 and RAID 6, which perform actual write operations as atomic read-modify-write sequences. That way, performance penalties of small random writes are reduced or avoided for such RAID layouts, by grouping them together and performing as batched sequential writes. Caching performed by bcache operates at the block device level, making itself file system-agnostic as long as the file system provides an embedded universally unique identifier (UUID); this requirement is satisfied by virtually all standard Linux file systems, as well as by swap partitions.
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The range came with Toshiba HDDs and optical media drives, available as 24X CD-ROMs or 4X DVD-ROMs. Hard drives ranged from 3 to 10 GB and ran at a slow 3300 RPM across the range. This could have been due to noise limitations, as the series is noted for its low noise output. Screens were available as 12.1 / 13.0 inch LCDs yet screen housing varied from model to model.
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Thailand is the world's second-biggest maker of hard disk drives (HDDs) after China, with Western Digital and Seagate Technology among the biggest producers. But problems may loom for Thailand's high-tech sector. In January 2015, the country's manufacturing index fell for the 22nd consecutive month, with production of goods like televisions and radios down 38 percent year-on-year. Manufacturers are relocating to nations where labour is cheaper than Thailand.
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2018 0200101Tom's Hardware: P. Alcorn, "Seagate Announces 14TB Barracuda Pro, IronWolf, and IronWolf Pro", Sept. 10th, 2018 This was followed by Western Digital in 2018Western Digital Ultrastar HC530 data sheet and Toshiba in 2019.AnandTech: Toshiba at CES2019: Worlds first 16TB TDMR HDD DebutsM. Abe & T. Hara, "Nearline TDMR HDDs with Industry’s Largest Capacity of 16 Tbytes", Toshiba Technology Review, Vol. 74., No. 6, pp. 8-11, Nov. 2019.
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In hard disk drives (HDDs), information is encoded using magnetic domains, and a change in the direction of their magnetization is associated with the logical level 1 while no change represents a logical 0. There are two recording methods: longitudinal and perpendicular. In the longitudinal method, the magnetization is normal to the surface. A transition region (domain walls) is formed between domains, in which the magnetic field exits the material.
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The Nimble CS-Series iSCSI and Fibre Channel storage array has 4 product lines for data centers available in each CS-Series. The product lines are CS200, CS300, CS500, and CS700 and combine both HDDs with SSDs in a hybrid fashion. In August, 2016, Nimble Storage updated their CS-Series arrays to the following: CS1000/H, CS3000, CS5000, and CS7000. Nimble Storage also provides an All-Flash Shelf to add to CS-Series arrays.
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Terry Johnson (March 14, 1935 – July 24, 2010) was an engineer and entrepreneur notable for his pioneering work on hard disk drives (HDD). Johnson's early career included engineering and management roles in magnetic recording at IBM (1964–70) and Memorex (1971–73). He then joined in the development of SuperDisk, a high-end, rotary actuator HDD funded by StorageTek. In 1980, he left StorageTek to found a startup, Miniscribe, a manufacturer of 5.25 inch HDDs.
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HDDs can be compressed to create additional space. In DOS and early Microsoft Windows, programs such as Stacker (DR-DOS except 6.0), SuperStor (DR DOS 6.0), DoubleSpace (MS-DOS 6.0–6.2), or DriveSpace (MS-DOS 6.22, Windows 9x) were used. This compression was done by creating a very large file on the partition, then storing the disk's data in this file. At startup, device drivers opened this file and assigned it a separate letter.
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PowerFlex uses storage and compute resources of commodity hardware. It combines HDDs, SSDs, and PCIe flash cards to create a virtual pool of block storage with varying performance tiers. It features on-demand performance and storage scalability, as well as enterprise- grade data protection, multi-tenant capabilities, and add-on enterprise features such as QoS, thin provisioning and snapshots. PowerFlex operates on multiple hardware platforms and supports physical and/or virtual application servers.
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The domains rotate sideways to a halfway position that weakens the readability of the domain and relieves the magnetic stresses. A write head magnetises a region by generating a strong local magnetic field, and a read head detects the magnetisation of the regions. Early HDDs used an electromagnet both to magnetise the region and to then read its magnetic field by using electromagnetic induction. Later versions of inductive heads included Metal In Gap (MIG) heads and thin film heads.
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His technical focus included Microwave Assisted Magnetic Recording (MAMR)Y. Shiroishi, "Microwave assisted magnetic recording and magnetic storage device", US Patent 9105279 2015/8/11 (In 2017, MAMR-based HDDs were announced by Western Digital which had purchased Hitachi GST)Western Digital press release, San Jose, CA, Oct 11, 2017). Shiroishi was the chairperson of the technical committee for Storage Research Consortium (SRC) from 2007 to 2012Storage Research Consortium: 28th SRC Technical Review, 17 Nov, 2009.
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Starting in the late 1980s, driven by the volume of IBM compatible PCs, HDDs became routinely available pre-formatted with a compatible low-level format. At the same time, the industry moved from historical (dumb) bit serial interfaces to modern (intelligent) bit serial interfaces and word serial interfaces wherein the low level format was performed at the factory. Accordingly, it is not possible for an end user to low-level format a modern hard disk drive.
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Two Seagate Barracuda drives, from 2003 and 2009 - respectively 160GB and 1TB. Seagate offers capacities up to 16TB. The highest-capacity desktop HDDs had 16 TB in late 2019. The capacity of a hard disk drive, as reported by an operating system to the end user, is smaller than the amount stated by the manufacturer for several reasons: the operating system using some space, use of some space for data redundancy, and space use for file system structures.
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Diagram of HDD manufacturer consolidation More than 200 companies have manufactured HDDs over time, but consolidations have concentrated production to just three manufacturers today: Western Digital, Seagate, and Toshiba. Production is mainly in the Pacific rim. Worldwide revenue for disk storage declined eight percent per year, from a peak of $38 billion in 2012 to $22 billion (estimated) in 2019. Production of HDD storage grew 15% per year during 2011–2017, from 335 to 780 exabytes per year.
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Thailand's economy weathered a difficult period and then climbed out of recession in the second half as investment and consumption improved. Thailand Board of Investment (BOI) nurture along many new projects to invigorate business, with 1 573 project applications submitted in 2009. BOI-approved investment covered a wide spectrum of sectors, from services, transport and industrial estates to electronics, eco-car parts and alternative energy. High-tech businesses engaged in the manufacture of telecommunication parts, semiconductors, HDDs, automotive electronics and many more.
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Over the next five years, he advanced to Director of Engineering at StorageTek. In 1980, Johnson left StorageTek and in May of that year, he attended the National Computer Conference (NCC) at Anaheim with Roy Applequist. Finis ConnerConner CP340 family of HDDs, Computer History Museum had rented suites at a hotel at NCC to showcase the newly-developed Shugart Technology's ST506Seagate ST506 HDD, Computer History Museum drive. During their discussion, Shugart encouraged Johnson to start his own company building a competitive product.
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Research into the ERB primarily utilizes virtual reality driving simulators to mimic real life driving scenarios while eliminating situational variability. In order to examine HUDs and HDDs, studies often compare hazard reaction time, situational awareness, and quality of driving (such as speed consistency) using both systems. The extent of the ERB on different demographics, particularly those of age and experience level, are of particular interest. The interaction between work-load and the influence of ERB are also frequently examined for research.
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The 0671 first shipped in 1987. Developed under the code name "Lee" at IBM Rochester, MN, it was an up to 316 MB ESDI full height 5¼-inch HDD with up to 8 130 mm disks depending upon model. This was IBM's first usage of a thin metal film as the disk's recording surface. In 1988 it shipped as part of the 9404 System Unit of the IBM AS/400 system which contained two, or optionally three of these HDDs.
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Serial General Purpose Input/Output (SGPIO) is a four-signal (or four-wire) bus used between a host bus adapter (HBA) and a backplane. Of the four signals, three are driven by the HBA and one by the backplane. Typically, the HBA is a storage controller located inside a server, desktop, rack or workstation computer that interfaces with hard disk drives (HDDs) to store and retrieve data. It is considered an extension of the general-purpose input/output (GPIO) concept.
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Servers commonly have a backplane to attach hot swappable hard drives; backplane pins pass directly into hard drive sockets without cables. They may have single connector to connect one disk array controller or multiple connectors that can be connected to one or more controllers in arbitrary way. Backplanes are commonly found in disk enclosures, disk arrays, and servers. Backplanes for SAS and SATA HDDs most commonly use the SGPIO protocol as means of communication between the host adapter and the backplane.
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Official HD Loader is extracted and released to the internet as a retaliation to the free library files used in its creation. 0.6d - the first unofficial version that improved game compatibility. 0.7c - fix for Suikoden V, patches for 48bit HDDs (up to 2 Terabytes), DMA modes (UDMA/MDMA) and DVD9 fix to allow dual layer games to be played were added. A stable GUI Patching app was created and allowed one to choose which patches and other various edits to apply to an Official unpatched version.
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Without support for TRIM, the SSD would be unaware of this data being invalid and would unnecessarily continue to rewrite it during garbage collection causing further wear on the SSD. It is beneficial to make some changes that prevent SSDs from being treated more like HDDs, for example cancelling defragmentation, not filling them to more than about 75% of capacity, not storing frequently written-to files such as log and temporary files on them if a hard drive is available, and enabling the TRIM process.
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Ekaterinburg technicians also celebrate the last July Friday. Before 2010 there were spontaneous gatherings, and since 2010 the event received official permission from Ekaterinburg authorities to be annually held near famous Keyboard monument in the city centre with support from IT companies. There are "sysadmin competitions" between participants: they throw defunct PC mice to reach maximum distance and also throw such mice (with their "tails" cut out) within an empty distant computer case used as basket. Additionally, they powerlift a bundle of unused HDDs.
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Load/unload technology relies on the heads being lifted off the platters into a safe location, thus eliminating the risks of wear and stiction altogether. The first HDD RAMAC and most early disk drives used complex mechanisms to load and unload the heads. Modern HDDs use ramp loading, first introduced by Memorex in 1967, to load/unload onto plastic "ramps" near the outer disk edge. Addressing shock robustness, IBM also created a technology for their ThinkPad line of laptop computers called the Active Protection System.
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Cost per bit for SSDs is falling, and the price premium over HDDs has narrowed. The primary characteristics of an HDD are its capacity and performance. Capacity is specified in unit prefixes corresponding to powers of : a 1-terabyte (TB) drive has a capacity of gigabytes (GB; where 1 gigabyte = bytes). Typically, some of an HDD's capacity is unavailable to the user because it is used by the file system and the computer operating system, and possibly inbuilt redundancy for error correction and recovery.
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Another technology used to overcome thermal effects to allow greater recording densities is perpendicular recording, first shipped in 2005, and used in certain HDDs. In 2004, a higher-density recording media was introduced, consisting of coupled soft and hard magnetic layers. So-called exchange spring media magnetic storage technology, also known as exchange coupled composite media, allows good writability due to the write-assist nature of the soft layer. However, the thermal stability is determined only by the hardest layer and not influenced by the soft layer.
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In the mid-to-late 1980s the similarly sized Fujitsu Eagle, which used (coincidentally) 10.5-inch platters, was a popular product. With increasing sales of microcomputers having built in floppy-disk drives (FDDs), HDDs that would fit to the FDD mountings became desirable. Starting with the Shugart Associates SA1000 HDD Form factors, initially followed those of 8-inch, 5½-inch, and 3½-inch floppy disk drives. Although referred to by these nominal sizes, the actual sizes for those three drives respectively are 9.5″, 5.75″ and 4″ wide.
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Device configuration overlay (DCO) is a hidden area on many of today's hard disk drives (HDDs). Usually when information is stored in either the DCO or host protected area (HPA), it is not accessible by the BIOS, OS, or the user. However, certain tools can be used to modify the HPA or DCO. The system uses the IDENTIFY_DEVICE command to determine the supported features of a given hard drive, but the DCO can report to this command that supported features are nonexistent or that the drive is smaller than it actually is.
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When Mojave is installed, it will convert solid-state drives (SSDs), hard disk drives (HDDs), and Fusion Drives, from HFS Plus to APFS. On Fusion Drives using APFS, files will be moved to the SSD based on the file's frequency of use and its SSD performance profile. APFS will also store all metadata for a Fusion Drive's file system on the SSD. New data protections require applications to get permission from the user before using the Mac camera and microphone or accessing system data like user Mail history and Messages database.
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SSDs can use traditional HDD interfaces and form factors, or newer interfaces and form factors that exploit specific advantages of the flash memory in SSDs. Traditional interfaces (e.g. SATA and SAS) and standard HDD form factors allow such SSDs to be used as drop-in replacements for HDDs in computers and other devices. Newer form factors such as mSATA, M.2, U.2, NF1, XFMEXPRESS and EDSFF (formerly known as Ruler SSD) and higher speed interfaces such as NVM Express (NVMe) over PCI Express can further increase performance over HDD performance.
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Fixed-block architecture (FBA) is an IBM term for the hard disk drive (HDD) layout in which each addressable block (more commonly, sector) on the disk has the same size, utilizing 4 byte block numbers and a new set of command codes. FBA as a term was created and used by IBM for its 3310 and 3370 HDDs beginning in 1979 to distinguish such drives as IBM transitioned away from their variable record size format used on IBM's mainframe hard disk drives beginning in 1964 with its System/360.
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As time progressed HDDs were able to store more information and the parts became much smaller. In 1976 the first solid-state drive (SSD) was made by Dataram and could store up to 2 MB. The SSD did not become popular until 2001 when the SSD industry's revenues reached $25 million a year. The reason for this slow growth was that early SSDs were expensive. In 1978 1 GB would have cost $1 million. Even in 2001, Adtron’s S35PC 3.5” SSD drive which had 14 GB storage cost $42,000.
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S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology; often written as SMART) is a monitoring system included in computer hard disk drives (HDDs), solid-state drives (SSDs), and eMMC drives. Its primary function is to detect and report various indicators of drive reliability with the intent of anticipating imminent hardware failures. When S.M.A.R.T. data indicates a possible imminent drive failure, software running on the host system may notify the user so preventive action can be taken to prevent data loss, and the failing drive can be replaced and data integrity maintained.
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Data is stored by a computer using a variety of media. Hard disk drives (HDDs) are found in virtually all older computers, due to their high capacity and low cost, but solid-state drives (SSDs) are faster and more power efficient, although currently more expensive than hard drives in terms of dollar per gigabyte, so are often found in personal computers built post-2007. SSDs use flash memory, which stores data on MOS memory chips consisting of floating-gate MOSFET memory cells. Some systems may use a disk array controller for greater performance or reliability.
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Boron is a component of neodymium magnets (Nd2Fe14B), which are among the strongest type of permanent magnet. These magnets are found in a variety of electromechanical and electronic devices, such as magnetic resonance imaging (MRI) medical imaging systems, in compact and relatively small motors and actuators. As examples, computer HDDs (hard disk drives), CD (compact disk) and DVD (digital versatile disk) players rely on neodymium magnet motors to deliver intense rotary power in a remarkably compact package. In mobile phones 'Neo' magnets provide the magnetic field which allows tiny speakers to deliver appreciable audio power.
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Partial updating of data is difficult with SMR. Data will be written to adjacent tracks that do not need to be rewritten. Shingled magnetic recording (SMR) is a magnetic storage data recording technology used in hard disk drives (HDDs) to increase storage density and overall per-drive storage capacity. Conventional hard disk drives record data by writing non-overlapping magnetic tracks parallel to each other (perpendicular magnetic recording, PMR), while shingled recording writes new tracks that overlap part of the previously written magnetic track, leaving the previous track narrower and allowing for higher track density.
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The additional per-sector space can be used by hardware RAID controllers or applications for storing Data Integrity Field (DIF) or Data Integrity Extensions (DIX) data, resulting in higher reliability and prevention of silent data corruption. ; Consumer electronics HDDs : They include drives embedded into digital video recorders and automotive vehicles. The former are configured to provide a guaranteed streaming capacity, even in the face of read and write errors, while the latter are built to resist larger amounts of shock. They usually spin at a speed of 5400 RPM.
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Using flash memory (NAND memory devices) for caching allows Linux kernel to service random disk IO with better performance than without the cache. This caching applies to all disk content, not just the page file or system binaries. Flash memory based devices are usually a magnitude faster than spinning HDDs for random IO, but with less advantage or even slower in sequential read/writes. By default, flashcache caches all full blocksize IOs, but can be configured to only cache random IO whilst ignoring sequential IO. Similar technology exists in Microsoft Windows as ReadyBoost since Windows Vista.
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Other examples of secondary storage technologies include USB flash drives, floppy disks, magnetic tape, paper tape, punched cards, and RAM disks. Once the disk read/write head on HDDs reaches the proper placement and the data, subsequent data on the track are very fast to access. To reduce the seek time and rotational latency, data are transferred to and from disks in large contiguous blocks. Sequential or block access on disks is orders of magnitude faster than random access, and many sophisticated paradigms have been developed to design efficient algorithms based upon sequential and block access.
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Usually, memory cards and HDDs use the FAT file system, while optical discs employ UDF or ISO 9660. At the file system level, the structure of AVCHD is derived from the Blu-ray Disc specification, but is not identical to it. In particular, it uses legacy "8.3" file naming convention, while Blu-ray Discs utilize long filenames (this may be caused by the fact that FAT implementations utilizing long file names are patented by Microsoft and are licensed on a per unit sold basis). Another difference is location of the BDMV directory, which contains media files.
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The size and shape of any device is largely driven by the size and shape of the components used to make that device. Traditional HDDs and optical drives are designed around the rotating platter(s) or optical disc along with the spindle motor inside. If an SSD is made up of various interconnected integrated circuits (ICs) and an interface connector, then its shape is no longer limited to the shape of rotating media drives. Some solid state storage solutions come in a larger chassis that may even be a rack-mount form factor with numerous SSDs inside.
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On January 14, 2008, EMC Corporation (EMC) became the first enterprise storage vendor to ship flash-based SSDs into its product portfolio when it announced it had selected STEC, Inc.'s Zeus-IOPS SSDs for its Symmetrix DMX systems. In 2008, Sun released the Sun Storage 7000 Unified Storage Systems (codenamed Amber Road), which use both solid state drives and conventional hard drives to take advantage of the speed offered by SSDs and the economy and capacity offered by conventional HDDs. Dell began to offer optional 256 GB solid state drives on select notebook models in January 2009.
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USB Attached SCSI (UAS) or USB Attached SCSI Protocol (UASP) is a computer protocol used to move data to and from USB storage devices such as hard drives (HDDs), solid-state drives (SSDs), and thumb drives. UAS depends on the USB protocol, and uses the standard SCSI command set. Use of UAS generally provides faster transfers compared to the older USB Mass Storage Bulk-Only Transport (BOT) drivers. UAS was introduced as part of the USB 3.0 standard, but can also be used with devices complying with the slower USB 2.0 standard, assuming use of compatible hardware, firmware and drivers.
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Wear leveling (also written as wear levelling) is a technique Wear leveling techniques for flash EEPROM systems. for prolonging the service life of some kinds of erasable computer storage media, such as flash memory, which is used in solid-state drives (SSDs) and USB flash drives, and phase-change memory. There are several wear leveling mechanisms that provide varying levels of longevity enhancement in such memory systems. The term preemptive wear leveling (PWL) has been used by Western Digital to describe their preservation technique used on hard disk drives (HDDs) designed for storing audio and video data.
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Meanwhile, several very large Japanese manufacturing firms were entering the market. The supercomputer market was too small to support more than a handful of companies, so CDC started looking for other markets. One of these was the hard disk drive (HDD) market. Magnetic Peripherals Inc., later Imprimis Technology was originally a joint venture with Honeywell formed in 1975 to manufacture HDDs for both companies. CII-Honeywell Bull later purchased a 3 percent interest in MPI from Honeywell. Sperry became a partner in 1983 with 17 percent, making the ownership split CDC (67%) and Honeywell (17%). MPI was a captive supplier to its parents.
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Seagate Technology (then called Shugart Technology) was incorporated on November 1, 1978, and commenced operations with co-founders Al Shugart, Tom Mitchell, Doug Mahon, Finis Conner and Syed Iftikar in October 1979.Seagate Technology Prospectus, September 24, 1981, p.4 The company came into being when Conner approached Shugart with the idea of starting a new company to develop 5.25-inch HDDs which Conner predicted would be a coming economic boom in the disk drive market. The name was changed to Seagate Technology to avoid a lawsuit from Xerox's subsidiary Shugart Associates (also founded by Shugart).
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With this kit, only the SCPH-30000 model of PlayStation 2 is officially supported. The kit does though work equally well with models newer than SCPH-30000 with the exception that the Ethernet connection tended to freeze after a short period of use. Thus the newer SCPH-50000 PlayStation 2 model will only work correctly with PS2 Linux with an updated network adapter driver, which must be transferred to the PlayStation 2 HDD by using either an older model PlayStation 2 to transfer the driver or a Linux PC with an IDE port. Both methods involve swapping HDDs.
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IBM Enters OEM Market For Winchester Disk Drives, Electronic News, September 14, 1981 By 1996, IBM had stopped making hard disk drives unique to its systems and was offering all its HDDs as an original equipment manufacturer (OEM).1996 Disk/Trend Report – Rigid Disk Drives, Specifications SectionIBM's disk drive family has three new members, INFOWORLD, October 17, 1994, p. 40 IBM uses many terms to describe its various magnetic disk drives, such as direct access storage device, disk file and diskette file. Here, the current industry standard terms, hard disk drive and floppy disk drive, are used.
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Examples are: transaction processing databases, internet infrastructure (email, webserver, e-commerce), scientific computing software, and nearline storage management software. Enterprise drives commonly operate continuously ("24/7") in demanding environments while delivering the highest possible performance without sacrificing reliability. Maximum capacity is not the primary goal, and as a result the drives are often offered in capacities that are relatively low in relation to their cost. : The fastest enterprise HDDs spin at 10,000 or 15,000 rpm, and can achieve sequential media transfer speeds above 1.6 Gbit/s and a sustained transfer rate up to 1 Gbit/s.
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The AT Attachment (ATA) hard disk interface is directly descended from the 16-bit ISA of the PC/AT. ATA has its origins in hardcards that integrated a hard disk drive (HDD) and a hard disk controller (HDC) onto one card. This was at best awkward and at worst damaging to the motherboard, as ISA slots were not designed to support such heavy devices as HDDs. The next generation of Integrated Drive Electronics drives moved both the drive and controller to a drive bay and used a ribbon cable and a very simple interface board to connect it to an ISA slot.
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DEC disk platters DEC was both a manufacturer and a buyer of magnetic disk storage, offering more than 100 different models of hard disk drive (HDD) and floppy disk drive (FDD) during its existence.DEC disk history In the 1970s, it was the single largest OEM purchaser of HDDs, procuring from Diablo, Control Data Corporation, Information Storage Systems, and Memorex, among others. DEC's first internally developed HDD was the RS08, a 256 kWord fixed-head contact-start-stop drive using plated media; it shipped in 1969. Beginning in the 1970s, DEC moved first its HDD manufacturing and then its mass storage development labs to Colorado Springs.
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In computer storage, the standard RAID levels comprise a basic set of RAID (redundant array of independent disks) configurations that employ the techniques of striping, mirroring, or parity to create large reliable data stores from multiple general-purpose computer hard disk drives (HDDs). The most common types are RAID 0 (striping), RAID 1 (mirroring) and its variants, RAID 5 (distributed parity), and RAID 6 (dual parity). RAID levels and their associated data formats are standardized by the Storage Networking Industry Association (SNIA) in the Common RAID Disk Drive Format (DDF) standard. The numerical values only serve as identifiers and do not signify performance, reliability, generation, or any other metric.
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These storage arrays include: • The Quantum F-Series: A line of fast, highly available NVMe SSD flash storage arrays for editing, rendering, and processing of video content and other large unstructured datasets. • Quantum QXS-Series: A line of high performance, reliable hybrid storage arrays, offered with either HDDs, SSDs, or some combination of the two. Customers deploy the StorNext file system with a combination of NVMe storage and more traditional SSD and HDD storage to balance cost and performance. StorNext software can also manage data across different types, or pools, of storage, such as public cloud object stores and disk-based object storage systems.
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Over time, several technologies have been incorporated into subsequent versions of Windows to improve the performance of the operating system on traditional hard disk drives (HDD) with rotating platters. Since Solid state drives (SSD) differ from mechanical HDDs in some key areas (no moving parts, write amplification, limited number of erase cycles allowed for reliable operation), it is beneficial to disable certain optimizations and add others, specifically for SSDs. Windows 7 incorporates many engineering changes to reduce the frequency of writes and flushes, which benefit SSDs in particular since each write operation wears the flash memory. Windows 7 also makes use of the TRIM command.
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User instigated low-level formatting (LLF) of hard disk drives was common for minicomputer and personal computer systems until the 1990s. IBM and other mainframe system vendors typically supplied their hard disk drives (or media in the case of removable media HDDs) with a low-level format. Typically this involved subdividing each track on the disk into one or more blocks which would contain the user data and associated control information. Different computers used different block sizes and IBM notably used variable block sizes but the popularity of the IBM PC caused the industry to adopt a standard of 512 user data bytes per block by the middle 1980s.
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Not caching the sequential I/O also helps in extending the lifetime of SSDs used as caches. Write amplification is avoided by not performing random writes to SSDs; instead, all random writes to SSD caches are always combined into block-level writes, ending up with rewriting only the complete erase blocks on SSDs. Both write-back and write-through (which is the default) policies are supported for caching write operations. In case of the write-back policy, written data is stored inside the SSD caches first, and propagated to the HDDs later in a batched way while performing seek-friendly operations making bcache to act also as an I/O scheduler.
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For example, a RAID 1 array has about half the total capacity as a result of data mirroring, while a RAID 5 array with drives loses of capacity (which equals to the capacity of a single drive) due to storing parity information. RAID subsystems are multiple drives that appear to be one drive or more drives to the user, but provide fault tolerance. Most RAID vendors use checksums to improve data integrity at the block level. Some vendors design systems using HDDs with sectors of 520 bytes to contain 512 bytes of user data and eight checksum bytes, or by using separate 512-byte sectors for the checksum data.
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Any read request can be serviced and handled by any drive in the array; thus, depending on the nature of I/O load, random read performance of a RAID 1 array may equal up to the sum of each member's performance, while the write performance remains at the level of a single disk. However, if disks with different speeds are used in a RAID 1 array, overall write performance is equal to the speed of the slowest disk. Synthetic benchmarks show varying levels of performance improvements when multiple HDDs or SSDs are used in a RAID 1 setup, compared with single-drive performance. However, some synthetic benchmarks also show a drop in performance for the same comparison.
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Prior to the 1980s there was little standardization of sector sizes; disk drives had a maximum number of bits per track and various system manufacturers subdivided the track into different sector sizes to suit their OSes and applications. The popularity of the PC beginning in the 1980s and the advent of the IDE interface in the late 1980s led to a 512-byte sector becoming an industry standard sector size for HDDs and similar storage devices. In the 1970s IBM added fixed-block architecture Direct Access Storage Devices (FBA DASDs) to its line of CKD DASD. CKD DASD supported multiple variable length sectors while the IBM FBA DASD supported sector sizes of 512, 1024, 2048, or 4096 bytes.
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On spinning HDDs this does not adversely affect files that are sequentially written, randomly read, or are subsequently read using the same temporal pattern, but does affect sequential read after random write spatial data access patterns because of magnetic head could be only in one position at a time to read data from platter while fragmentation does no effect on SSD drives. Releases of ONTAP since 7.3.1 have included a number of techniques to optimize spatial data layout such as the reallocate command to perform scheduled and manual defragmentation, and the Write after Reading volume option which detects and automatically corrects suboptimal data access patterns caused by spatial fragmentation. Releases of ONTAP 8.1.
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53, No. 2, 2006 humanoid robot,K. Ohno and F. Nagashima, "Signal processor," Publication No.~WO2006064571, 2006 GPS,K. Ohno and S. Mori, "A GPS receiver," Domestic Patent, Publication No.~2005-221331, 2005 spatial information system,Nagata, S. Mori, K. Ohno and Y. Hirokawa, "Server system, user terminal, service providing method and service providing system using the server system and the user terminal," United States Patent, Publication No.~20060031410, 2006 etc. During this term, he was with the University of California at Berkeley as visiting fellow to continue to work on the fundamental research on control engineering.K. Ohno, R. Horowitz, “A Variable Structure Multi-rate State Estimator for Seeking Control of HDDs,” IEEE Trans.
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If supported by the SSD (not implemented on early devices), this optimizes when erase cycles are performed, reducing the need to erase blocks before each write and increasing write performance. Several tools and techniques that were implemented in the past to reduce the impact of the rotational latency of traditional HDDs, most notably disk defragmentation, SuperFetch, ReadyBoost, and application launch prefetching, involve reorganizing (rewriting) the data on the platters. Since SSDs have no moving platters, this reorganization has no advantages, and may instead shorten the life of the solid state memory. Therefore, these tools are by default disabled on SSDs in Windows 7, except for some early generation SSDs that might still benefit.
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In computing, a hybrid drive (solid state hybrid drive – SSHD) is a logical or physical storage device that combines a faster storage medium such as solid- state drive (SSD) with a higher-capacity hard disk drive (HDD). The intent is adding some of the speed of SSDs to the cost-effective storage capacity of traditional HDDs. The purpose of the SSD in a hybrid drive is to act as a cache for the data stored on the HDD, improving the overall performance by keeping copies of the most frequently used data on the faster SSD. There are two main configurations for implementing hybrid drives: dual-drive hybrid systems and solid-state hybrid drives.
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General concept for TDMR using multiple read elements Two-dimensional magnetic recording (TDMR) is a novel technology recently introduced in hard disk drives (HDD) used for computer data storage. Most of the world's data is recorded on HDDs, and there is continuous pressure on manufacturers to create greater data storage capacity in a given HDD form-factor and for a given cost. In an HDD, data is stored using magnetic recording on a rotating magnetic disk and is accessed through a write-head and read-head (or read-element). TDMR allows greater storage capacity by advantageously combining signals simultaneously from multiple read-back heads to enhance the recovery of one or more of data- tracks.
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The Hardcard provided the computer industry with the first one-inch- thick HDD, but it was an interface and form factor only compatible with the full length card slot of the ISA"Plug in Hardcard and turn your PC into an XT." "Size -1.0x4.2x13.4 inches." Plus Hardcard Promotional Brochure, (C) 1985 bus first introduced with the IBM PC. As such it had a thicker head disk assemblyThe Hardcard head disk assembly is the full 1-inch thick while the standard 1-inch HDD has both a printed circuit assembly and a head disk assembly in the 1-inch height. than the subsequently introduced 1-inch high standard form factor 3½-inch HDDs.
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HDD price per byte improved at the rate of −40% per year during 1988–1996, −51% per year during 1996–2003 and −34% per year during 2003–2010. The price improvement decelerated to −13% per year during 2011–2014, as areal density increase slowed and the 2011 Thailand floods damaged manufacturing facilities and have held at -11% per year during 2010–2017. The Federal Reserve Board has published a quality-adjusted price index for large-scale enterprise storage systems including three or more enterprise HDDs and associated controllers, racks and cables. Prices for these large-scale storage systems improved at the rate of ‒30% per year during 2004–2009 and ‒22% per year during 2009–2014.
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As of November 2016, available Storwize media sizes include 2.5-inch flash SSDs with up to 15.36 TB capacity and 3.5-inch Nearline-HDDs with up to 10 TB capacity, available for Storwize 5000, 7000 and SAN Volume Controller native attach. IBM Storwize Easy Tier will automatically manage and continually optimize data placement in mixed pools of nearline disks / standard disks / read-intensive Flash and enterprise-grade Flash SSDs, including from virtualized devices. Transparent Cloud Tiering for Swift- and S3-compatible object datastores can be used as a cold tier for incremental volume snapshots and volume archives without live production access. This allows keeping hourly time machine copies or archiving VM images including attached volumes at a price point somewhat closer to tape media.
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A PCI-attached IO Accelerator SSD An mSATA SSD with an external enclosure 512 GB Samsung 960 PRO NVMe M.2 SSD A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage. It is also sometimes called a solid-state device or a solid-state disk, even though SSDs lack the physical spinning disks and movable read–write heads used in hard disk drives (HDDs) and floppy disks. Compared with the electromechanical drives, SSDs are typically more resistant to physical shock, run silently, and have quicker access time and lower latency. SSDs store data in semiconductor cells.
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A 2 GB disk-on-a-module with PATA interface A disk-on-a-module (DOM) is a flash drive with either 40/44-pin Parallel ATA (PATA) or SATA interface, intended to be plugged directly into the motherboard and used as a computer hard disk drive (HDD). DOM devices emulate a traditional hard disk drive, resulting in no need for special drivers or other specific operating system support. DOMs are usually used in embedded systems, which are often deployed in harsh environments where mechanical HDDs would simply fail, or in thin clients because of small size, low power consumption and silent operation. storage capacities range from 4 MB to 128 GB with different variations in physical layouts, including vertical or horizontal orientation.
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However, modern systems profit enormously from the huge disk capacities currently available, since partially filled disks fragment much less than full disks, and on a high-capacity HDD, the same partition occupies a smaller range of cylinders, resulting in faster seeks. However, the average access time can never be lower than a half rotation of the platters, and platter rotation (measured in rpm) is the speed characteristic of HDDs which has experienced the slowest growth over the decades (compared to data transfer rate and seek time), so minimizing the number of seeks remains beneficial in most storage-heavy applications. Defragmentation is just that: ensuring that there is at most one seek per file, counting only the seeks to non-adjacent tracks.
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Speed maintenance is the extent to which a driver maintains a speed and adjusts their speed to suit traffic laws and environmental conditions. The use of HUDs appears to produce better speed maintenance in drivers under experimental conditions when compared to HDDs. It is theorized that this is because having the speedometer at the eye level of the vehicle operator allows for continuous monitoring of the vehicle's speed. HUD use also appears to increase general driving quality, including staying within road markings, and increased smoothness of driving and navigation abilities. Drivers’ capacity to focus on external cues, such as road texture, road demarcations and street signs is increased by using a seamless interface where focus on the road isn't interrupted to assess speed and other information.
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This policy aims to take different cache miss costs into account, and to make automatic adjustments to different load patterns. : This policy internally tracks sequential I/O operations so they can be routed around the cache, with different configurable thresholds for the differentiation between random I/O and sequential I/O operations. As a result, large contiguous I/O operations are left to be performed by the origin device because such data access patterns are suitable for HDDs, and because they avoid undesirable cache invalidation. ; stochastic multiqueue (smq) : The stochastic multiqueue (smq) policy performs in a similar way as the multiqueue policy, but requires fewer resources to operate; in particular, it uses substantially smaller amounts of main memory to track cached blocks.
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Modern hard disk drives appear to their host controller as a contiguous set of logical blocks, and the gross drive capacity is calculated by multiplying the number of blocks by the block size. This information is available from the manufacturer's product specification, and from the drive itself through use of operating system functions that invoke low-level drive commands. The gross capacity of older HDDs is calculated as the product of the number of cylinders per recording zone, the number of bytes per sector (most commonly 512), and the count of zones of the drive. Some modern SATA drives also report cylinder-head-sector (CHS) capacities, but these are not physical parameters because the reported values are constrained by historic operating system interfaces.
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SSDs based on volatile memory such as DRAM are characterized by very fast data access, generally less than 10 microseconds, and are used primarily to accelerate applications that would otherwise be held back by the latency of flash SSDs or traditional HDDs. DRAM-based SSDs usually incorporate either an internal battery or an external AC/DC adapter and backup storage systems to ensure data persistence while no power is being supplied to the drive from external sources. If power is lost, the battery provides power while all information is copied from random access memory (RAM) to back-up storage. When the power is restored, the information is copied back to the RAM from the back-up storage, and the SSD resumes normal operation (similar to the hibernate function used in modern operating systems).
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Due to their generally prohibitive cost versus HDDs at the time, until 2009, SSDs were mainly used in those aspects of mission critical applications where the speed of the storage system needed to be as high as possible. Since flash memory has become a common component of SSDs, the falling prices and increased densities have made it more cost-effective for many other applications. For instance, in the distributed computing environment, SSDs can be used as the building block for a distributed cache layer that temporarily absorbs the large volume of user requests to the slower HDD based backend storage system. This layer provides much higher bandwidth and lower latency than the storage system, and can be managed in a number of forms, such as distributed key-value database and distributed file system.
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In modern times and with the advent of larger drives and very fast RAID setups, users are capable of transferring 1016 bits in a reasonably short time, thus easily reaching the data corruption thresholds. As an example, ZFS creator Jeff Bonwick stated that the fast database at Greenplum, which is a database software company specializing in large-scale data warehousing and analytics, faces silent corruption every 15 minutes. As another example, a real-life study performed by NetApp on more than 1.5 million HDDs over 41 months found more than 400,000 silent data corruptions, out of which more than 30,000 were not detected by the hardware RAID controller. Another study, performed by CERN over six months and involving about 97 petabytes of data, found that about 128 megabytes of data became permanently corrupted.
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In computing, data recovery is a process of salvaging (retrieving) inaccessible, lost, corrupted, damaged or formatted data from secondary storage, removable media or files, when the data stored in them cannot be accessed in a usual way. The data is most often salvaged from storage media such as internal or external hard disk drives (HDDs), solid-state drives (SSDs), USB flash drives, magnetic tapes, CDs, DVDs, RAID subsystems, and other electronic devices. Recovery may be required due to physical damage to the storage devices or logical damage to the file system that prevents it from being mounted by the host operating system (OS). The most common data recovery scenario involves an operating system failure, malfunction of a storage device, logical failure of storage devices, accidental damage or deletion, etc.
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While it is generally impossible to perform a complete LLF on most modern hard drives (since the mid-1990s) outside the factory,Many enterprise class HDDs can be low-level formatted to block sizes other than 512 bytes; e.g., Seagate SAS drives support sector sizes of 512, 520, 524 or 528 bytes and can reformatted from one size to another. the term "low-level format" is still used for what could be called the reinitialization of a hard drive to its factory configuration (and even these terms may be misunderstood). The present ambiguity in the term low-level format seems to be due to both inconsistent documentation on web sites and the belief by many users that any process below a high-level (file system) format must be called a low-level format.
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Historically, most SSDs used buses such as SATA, SAS or Fibre Channel for interfacing with the rest of a computer system. Since SSDs became available in mass markets, SATA has become the most typical way for connecting SSDs in personal computers; however, SATA was designed primarily for interfacing with mechanical hard disk drives (HDDs), and it became increasingly inadequate for SSDs, which improved in speed over time. For example, within about 5 years of mass market mainstream adoption (2005–2010) many SSDs were already held back by the comparatively slow data rates available for hard drives—unlike hard disk drives, some SSDs are limited by the maximum throughput of SATA. High-end SSDs had been made using the PCI Express bus before NVMe, but using non- standard specification interfaces.
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9335 drive # 9331 Diskette Unit models 1 and 11 contained one 8-inch FDD while the models 2 and 12 contained one 5¼-inch FDD. # 9332 Direct Access Storage Device used the IBM 0667 HDD. # 9333 High Performance Disk Drive Subsystem used the IBM 0664 or IBM 0681 HDDs depending upon subsystem model # 9334 Disk Expansion Unit [To be determined] # 9335 Direct Access Storage Subsystem This HDD used in this subsystem was developed under the code name "Kestrel" at IBM Hursley, UK, and was an 850 MB HDD using three 14-inch disks with dual rotary actuators, each actuator accessing three surfaces with two heads per surface. The HDD was in the rack mountable 9335 announced as a part of the October 1986 IBM 9370 Information System announcement.
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Some laptops have very limited space on the installed SSD, instead relying on availability of cloud storage services for storing of user data; Chromebooks are a prominent example of this approach. A variety of external HDDs or NAS data storage servers with support of RAID technology can be attached to virtually any laptop over such interfaces as USB, FireWire, eSATA, or Thunderbolt, or over a wired or wireless network to further increase space for the storage of data. Many laptops also incorporate a card reader which allows for use of memory cards, such as those used for digital cameras, which are typically SD or microSD cards. This enables users to download digital pictures from an SD card onto a laptop, thus enabling them to delete the SD card's contents to free up space for taking new pictures.
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The computational storage technology minimizes the data movements in a cluster and also increases the processing horsepower of the cluster by augmenting power-efficient processing engines to the whole system. This technology can potentially be applied to both HDDs and SSDs; however, modern SSD architecture provides better tools for developing such technologies. The SSDs which can run user application in-place are called computational storage devices (CSDs). These storage units are augmentable processing resources, which means they are not designed to replace the high- end processors of modern servers. Instead, they can collaborate with the host’s CPU and augment their efficient processing horsepower to the system. The scientific article “Computational storage: an efficient and scalable platform for big data and HPC applications” which is published by Springer Publishing under open access policy (free for the public to access) shows the benefits of CSD utilization in the clusters.
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Late 2011 and early 2012 benchmarks using an SSHD consisting of a 750 GB HDD and 8 GB of NAND cache found that SSHDs did not offer SSD performance on random read/write and sequential read/write, but were faster than HDDs for application startup and shutdown. The 2011 benchmark included loading an image of a system that had been used heavily, running many applications, to bypass the performance advantage of a freshly-installed system; it found in real-world tests that performance was much closer to an SSD than to a mechanical HDD. Different benchmark tests found the SSHD to be between an HDD and SSD, but usually significantly slower than an SSD. In the case of uncached random access performance (multiple 4 KB random reads and writes) the SSHD was no faster than a comparable HDD; there is advantage only with data that is cached.
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8-, 5.25-, 3.5-, 2.5-, 1.8- and 1-inch HDDs, together with a ruler to show the size of platters and read-write heads A newer 2.5-inch (63.5 mm) 6,495 MB HDD compared to an older 5.25-inch full-height 110 MB HDD IBM's first hard disk drive, the IBM 350, used a stack of fifty 24-inch platters, stored 3.75 MB of data (approximately the size of one modern digital picture), and was of a size comparable to two large refrigerators. In 1962, IBM introduced its model 1311 disk, which used six 14-inch (nominal size) platters in a removable pack and was roughly the size of a washing machine. This became a standard platter size for many years, used also by other manufacturers. The IBM 2314 used platters of the same size in an eleven-high pack and introduced the "drive in a drawer" layout.
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In computer main memory, auxiliary storage and computer buses, data redundancy is the existence of data that is additional to the actual data and permits correction of errors in stored or transmitted data. The additional data can simply be a complete copy of the actual data, or only select pieces of data that allow detection of errors and reconstruction of lost or damaged data up to a certain level. For example, by including additional data checksums, ECC memory is capable of detecting and correcting single-bit errors within each memory word, while RAID 1 combines two hard disk drives (HDDs) into a logical storage unit that allows stored data to survive a complete failure of one drive. Data redundancy can also be used as a measure against silent data corruption; for example, file systems such as Btrfs and ZFS use data and metadata checksumming in combination with copies of stored data to detect silent data corruption and repair its effects.
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Eleftheriou performed basic research in noise-predictive detection, which found wide application in magnetic recording systems and spurred further research on advanced noise-predictive schemes for a variety of stationary and non-stationary noise sources. In this context, he developed the reduced state sequence detection approach, which is also the basic idea behind the so-called Noise-Predictive Maximum Likelihood (NPML) detection for magnetic recording. This work in its various instantiations, including iterative detection/decoding schemes, is the core technology of the read channel module in hard-disk drives (HDDs) and tape drive systems. The Eduard Rhein Foundation said Eleftheriou had "a pioneering role in the introduction of innovative digital signal processing and coding techniques into hard disk drives". In 2001, he started to work on a concept that IBM’s 1986 Nobel laureate Gerd Binnig had originated, namely, to use atomic force microscopy to not only image surfaces, but to also manipulate the surface of soft materials, such as polymers, and write information in the form of nanometer-scale indentations.
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The first disk drive to use removable media was the IBM 1311 drive. It was introduced in 1962 using the IBM 1316 disk pack to store two million characters. It was followed by the IBM 2311 (1964) using the IBM 1316 disk pack to store 5 megabyte, IBM 2314 (1965) using the IBM 2316 disk pack to store 29 megabytes, the IBM 3330 using 3336 disk packs to store 100 megabytes and the 3330-11 using the 3336-11 to store 200 megabytes.A partially disassembled IBM 350 (RAMAC)Memorex in 1968 shipped the first HDD, the Memorex 630, plug compatible to an IBM model 2311 marking the beginning of independent competition (Plug Compatible Manufacturers or PCMs) for HDDs attached to IBM systems. It was followed in 1969 by the Memorex 660, an IBM 2314 compatible, which was OEM'ed to DEC and resold as the RP02.Removable disk packs In 1964, Burroughs introduced the B-475 disk drive, with a head per track, as part of the B5500.Burroughs B-475 Disk Drive (circled) In 1970, IBM introduced the 2305 disk drive, with a head per track.
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Two SATA Express connectors (light gray) on a computer motherboard; to the right of them are common SATA connectors (dark gray) The Serial ATA (SATA) interface was designed primarily for interfacing with hard disk drives (HDDs), doubling its native speed with each major revision: maximum SATA transfer speeds went from 1.5 Gbit/s in SATA 1.0 (standardized in 2003), through 3 Gbit/s in SATA 2.0 (standardized in 2004), to 6 Gbit/s as provided by SATA 3.0 (standardized in 2009). SATA has also been selected as the interface for gradually more adopted solid-state drives (SSDs), but the need for a faster interface became apparent as the speed of SSDs and hybrid drives increased over time. As an example, some SSDs available in early 2009 were already well over the capabilities of SATA 1.0 and close to the SATA 2.0 maximum transfer speed, while in the second half of 2013 high-end consumer SSDs had already reached the SATA 3.0 speed limit, requiring an even faster interface. While evaluating different approaches to the required speed increase, designers of the SATA interface concluded that extending the SATA interface so it doubles its native speed to 12 Gbit/s would require more than two years, making that approach unsuitable for catching up with advancements in SSD technology.
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