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	Topics Solid-state drive Topic Home A solid-state drive (SSD) is a data storage deviceData storage device In computing, a data storage device—as the name implies—is a device for storing data.... that uses solid-state memoryComputer storage Computer storage, computer memory, and often casually memory refer to computer components, devices and recording... to store persistent dataData In general, data consists of propositions that reflect reality.... . Unlike flash-based memory cardMemory card UFCFISH Universal Transportable Memory Card Standard... s, an SSD emulates a hard disk drive, thus easily replacing it in most applications. An SSD using SRAMStatic random access memory Static random access memory is a type of semiconductor memory.... or DRAMDram Dram can mean several things:* For the imperial unit of volume see dram, commonly used to describe a measure of Scotc... (instead of flash memoryFlash memory Flash memory is a form of non-volatile computer memory that can be electrically erased and reprogrammed.... ) is often called a RAM-drive. The original usage of the term solid-state (from solid-state physicsSolid-state physics Solid-state physics, the largest branch of condensed matter physics, is the study of rigid matter, or solids.... ) refers to the use of semiconductor devices rather than electron tubesVacuum tube In electronics, a vacuum tube or valve is a device generally used to amplify, or otherwise modify, a signal by cont... , but has in this context been adopted to distinguish solid-state electronics from electromechanical devices as well. With no moving partsMoving parts Moving parts are the components of a device that undergo continuous or frequent motion, most commonly rotation.... , solid-state drives are inherently less fragile than harddisks and therefore also silent (unless a cooling fan is used); as there are no mechanical delays, they usually enjoy low access timeAccess time Access time is the time delay or latency between a request for access to an electronic system, and the access being granted ... and latencyLatency (engineering) Latency is a time delay between the moment something is initiated, and the moment one of its effects begins.... . SSDs have begun to appear in laptops, although they are at present substantially more expensive per unit of capacity than hard drives. History In 1978, the StorageTek company developed the first solid-state drive. In the mid-1980s Santa Clara Systems introduced BatRam, an array of 1 megabit DIPDual in-line package In microelectronics, a dual in-line package , sometimes called a DIL package, is an electronic device package with a r... RAM Chips and a custom controller card that emulated a hard disk. The package included a rechargeable battery to preserve the memory chip contents when the array was unpowered. The Sharp PC-5000Sharp PC-5000 The Sharp PC-5000 was a pioneering laptop computer, announced by Sharp Corporation of Japan in 1983.... , introduced in 1983, used 128 kilobyte (128 KiBKibibyte Overview A kibibyte is a unit of information or computer storage, abbreviated KiB.... ) solid-state storage cartridges, containing bubble memoryBubble memory Bubble memory is a type of non-volatile computer memory that uses a thin film of a magnetic material to hold small magnetize... . RAM "disks"RAM disk A RAM-Disk, Ramdisk or Ramdrive is a virtual solid state disk that uses a segment of active computer memory, RAM, as second... were popular as boot media in the 1980s, when hard drives were expensive, floppy drives were slow, and a few systems, such as the AmigaAmiga The Amiga is a family of home/personal computers originally developed by Amiga Corporation as an advanced home entertainment... series and the Apple IIgsApple IIGS The Apple IIGS, the fifth model inception of the Apple II, was the most powerful member of the Apple II series of personal c... , supported such booting. At the cost of some main memory, the system could be soft-rebooted and be back in the operating system in mere seconds instead of minutes. Some systems were batteryBattery (electricity) Overview In science and technology, a battery is a device that stores chemical energy and makes it available in an electrical form.... -backed so contents could persist when the system was shut down. In 1995 M-SystemsM-Systems M-Systems was a Nasdaq-listed Israeli producer of flash storage memory founded in 1989, best known for its DiskOnChip 2000... introduced flash-based solid-state drives.. Since then, SSDs have been used successfully as hard disk drive replacements by the military and aerospace industries, as well as other mission-critical applications. These applications require the exceptional mean time between failures (MTBF) rates that solid-state drives achieve, by virtue of their ability to withstand extreme shock, vibration and temperature ranges. The Gigabyte i-RAM uses standard DDR modules and connects to its host via Serial ATASerial ATA In computer hardware, Serial ATA is a computer bus technology primarily designed for transfer of data to and from a hard dis... . This card can use the system's standby power (also used for Wake-on-LAN and similar features) to maintain its RAM contents even with the system powered off, and includes a battery that can retain the data when the system is completely disconnected from power. Architecture and function An SSD is commonly composed of either NAND flash non-volatile memoryNon-volatile memory Non-volatile memory, or non-volatile storage, is computer memory that can retain the stored information even when not ... or DRAMDram Dram can mean several things:* For the imperial unit of volume see dram, commonly used to describe a measure of Scotc... volatile memoryVolatile memory Volatile memory, or volatile storage, is computer memory that requires power to maintain the stored information, unlik... . Most SSD manufacturers use non-volatile flash memory to create more rugged and compact alternatives for the consumer market. These flash memory-based SSDs, also known as flash driveFlash drive A flash drive is a storage device that uses flash memory rather than conventional spinning platters to store data.... s, do not require batteries, allowing makers to replicate standard disk drive form factors (1.8-inch, 2.5-inch, and 3.5-inch). In addition, non-volatility allows flash SSDs to retain memory even during sudden power outages, ensuring data retrievability. Though flash SSDs are significantly slower than DRAM, they still perform better than traditional hard drives, at least with regard to reads. Flash SSDs have no moving parts, thus eliminating spin-up time altogether, and greatly reducing seek time, latency and other delays inherent in conventional electro-mechanical disks. SSDs based on volatile memory such as DRAM are characterized by very fast data access, generally less than 0.01 milliseconds (over 250 times faster than the fastest hard drives in 2004), and are used primarily to accelerate applications that would otherwise be held back by the latencyMemory latency In computing, memory latency is the time between initiating a request for a byte or word in memory until it is retrieved.... of disk drives. DRAM-based SSDs sometimes incorporate internal batteryBattery (electricity) In science and technology, a battery is a device that stores chemical energy and makes it available in an electrical form.... and backupBackup In the field of information technology, backup refers to the copying of data so that these additional copies may be restor... storage systems to ensure data persistence. If power is lost for any reason, the battery keeps the unit powered for sufficient time to allow the copying of all data from random access memoryRandom access memory Random-access memory refers to data storage formats and equipment that allow the storing data to be accessed in any order &... (RAM) to the back-up storage. Then, when the power is restored, data is copied back to RAM from the back-up storage, and the SSD resumes normal operation. (This is not unlike the "hibernate" function used in modern operating systems, which saves the entire contents of memory to nonvolatile storage before power-down, to be rewritten into memory upon power-up.) Solid-state drives are especially useful on computers that already have the maximum amount of supported RAM. For example, some computer systems built on the x86-32 architecture can effectively be extended beyond the 4 GBGigabyte A gigabyte is a unit of information or computer storage equal to one billion bytes.... limit by putting the paging filePaging In computer operating systems, paging memory allocation algorithms divide computer memory into small partitions, and allocat... or swap file on an SSD. Owing to the bandwidth bottleneckVon Neumann architecture A von Neumann architecture is a computer design model that uses a single storage structure to hold both instructions and dat... of the busComputer bus In computer architecture, a bus is a subsystem that transfers data or power between computer components inside a computer or... they connect to, SSDs cannot read and write data as fast as main RAM can, but they are far faster than any mechanical hard drive. Placing the swap file on an SSD, as opposed to a traditional hard drive, can therefore provide a significant performance increase. DRAM-based SSDs may also work as a buffer cache mechanism. Whenever data is written to memory, the corresponding block in memory is marked as dirty, and all dirty blocks can be flushed to the actual hard drive based on the following two criteria: Time (e.g. every 10 seconds, flush all dirty data); Threshold (when the ratio of dirty data to SSD size exceeds some predetermined value, flush the dirty data). Modern models carry lithium-ion batteries as back-up in case of a power outage, or to allow transfer to another computer. Comparison with hard disk drives A comparison (with benchmarks) of SSDs, Secure Digital High Capacity (SDHC) drives, and hard disk drives (HDDs) is given in the reference. Advantages Faster start-up – as no spin-upSpin-up Spin-up refers to the period of time taken by a traditional hard disk drive to accelerate its platters from a stopped state... is required. (RAM & Flash) Typically fast random accessRandom access Summary In computer science, random access is the ability to access a random element of a group in equal time.... for reading – as there is no read/write headDisk read-and-write head Disk read/write heads are mechanisms that read data from or write data to disk drives.... to move. (RAM & Flash) Extremely low read and write latency times – as SSD seek-times are orders of magnitude lower than the best current hard disk drives. (RAM) In applications where hard disk seeks are the limiting factor this results in faster boot and application launch times ( see Amdahl's lawAmdahl's law Amdahl's law, named after computer architect Gene Amdahl, is used to find the maximum expected improvement to... ). (RAM) No noise – a lack of moving parts makes SSDs completely silent, unless, as in the case of some high-end and high-capacity models, they have cooling fansComputer cooling This computer cooling article covers the many ways that potentially damaging heat is relieved from electronic computers.... attached. (RAM & Flash) For low-capacity SSDs, low power consumption and heat production when in active use - although high-end SSDs and DRAM-based SSDs may have significantly higher power requirements. High mechanical reliability – the lack of moving parts almost eliminates the risk of mechanical failure. (RAM & Flash) Ability to endure extreme shock, high altitude, vibration and extremes of temperature – once again because there are no moving parts. This makes SSDs useful for laptopLaptop A laptop computer or simply laptop is a small mobile personal computer, usually weighing from one to three kilograms, ... s, mobile computers, and devices that operate in extreme conditions. (Flash) Relatively deterministic read performance – unlike hard disk drives, performance of SSDs is almost constant and deterministic across the entire storage. This is because the seek timeSeek time Seek time is one of the several delays associated with reading or writing data on a computer's disk drive.... is almost constant and is not dependent on the physical location of the data, and so, file fragmentationFile system fragmentation In computing, file system fragmentation, sometimes called file system aging, is the inability of a file system to lay ... has almost no impact on read performance. For low-capacity SSDs, lower weight and size – although size and weight per unit storage are still better for traditional hard drives, and microdrives allow up to 20 GB storage in a CompactFlash 42.8×36.4×5 mm (1.7×1.4×.2 in) form-factor. Up to 256 GB, SSDs are currently lighter than hard drives of the same capacity. Disadvantages Price – as of mid-2008, flash memory prices are still considerably more costly per gigabyte than are comparable conventional hard drives: around USD 3.50 per GB compared to typically less than USD 0.40 for mechanical drives. Capacity – although currently far lower than that of conventional hard drives, SSD capacity is predicted to increase rapidly, with experimental drives of up to 1 TB in test. Higher vulnerability to certain types of effects, including abrupt power loss (especially DRAM based SSDs), magnetic fields and electric/static charges, in comparison to normal HDDs (which store the data inside a Faraday cageFaraday cage A Faraday cage or Faraday shield is an enclosure formed by conducting material, or by a mesh of such material.... ). Limited write cycles – flash-memory cells will often wear out after 10,000-100,000 write cycles, while high endurance cells may have an endurance of 1–5 million write cycles (many log files, file allocation tables, and other commonly used parts of the file system exceed this over the lifetime of a computer . Special file systems or firmware designs can mitigate this problem by spreading writes over the entire device (so-called wear levellingWear levelling Wear levelling is a technique for prolonging the service life of some kinds of erasable computer storage media, such as flas... ), rather than rewriting files in place. This problem is being improved all the time, with consequent increases in expected lifespans. Today's drives can last up to 20 years with average usage. An example for the lifetime of SSD is explained in detail . SSDs based on DRAM, however, do not suffer from this problem. Slower write speeds – as erase blocks on flash-based SSDs generally are quite large, they are far slower than conventional disks for random writes and therefore vulnerable to write fragmentation, and in some cases for sequential writes. SSDs based on DRAM do not suffer from this problem. Lower storage density – hard disks can store more data per unit volume than DRAM or flash SSDs, except for very low capacity/small devices. Higher power consumption at idle or under low workloads laptop battery runtimes decrease when using an SSD over a 7200 RPM 2.5" laptop hard drive, flash drives also take more power per gigabyte. Commercialization Cost and capacity Until recently, solid-state drives were too costly for mobile computing. As flash manufacturers transition from NOR flash to single-level cellSingle-level cell Flash memory stores data in individual memory cells, which are made of floating-gate transistors.... (SLC) NAND flash and most recently to multi-level cell (MLC) NAND flash to maximize silicon die usage and reduce associated costs, "solid-state disks" are now being more accurately renamed "solid-state drives" – they have no disks but function as drives – for mobile computing in the enterprise and consumer electronics space. This technological trend is accompanied by an annual 50% decline in raw flash material costs, while capacities continue to double at the same rate. As a result, flash-based solid-state drives are becoming increasingly popular in markets such as notebook PCs and sub-notebooks for enterprises, Ultra-Mobile PCUltra-Mobile PC The Ultra-Mobile PC, previously known by its codename Project Origami, is a specification for a small form factor tabl... s (UMPC), and Tablet PCTablet PC A tablet PC is a notebook- or slate-shaped mobile computer.... s for the healthcare and consumer electronics sectors. Major PC companies have now started to offer such technology. The capacity of these drives varies from 12 GB to 256 GB. Availability Even though solid-state drive (SSD) technology has been marketed to the military and niche industrial markets since the mid-1990s, it is only recently that the enterprise sector has taken notice of the benefits that SSDs can offer, as key SSD technologies emerge, prices drop and new case studies, along with analyst reports, are published. Along with the emerging enterprise market, SSDs have been appearing in ultra-mobile PCs and a few lightweight laptop systems, adding a US$ $600 to $1000 premium to the price of a HDD-equipped laptop, depending on the capacity, form factor and transfer speeds. Only a handful of companies offer large (128 GBGB Summary GB may stand for:* Gb* GB in Belgium... or larger) SSD drives with write speeds adequate for replacing traditional drives, and these drives are available in limited quantities and are very expensive. Already some manufacturers have begun shipping affordable, fast, energy-efficient drives priced at $350 to computer manufacturers. For low-end applications, a USB memory stick may be used as a Flash hard drive for $10 to $100 or so, depending on capacity, or a CompactFlashCompactFlash CompactFlash was originally a type of data storage device, used in portable electronic devices.... card may be paired with a CF-to-IDE or CF-to-SATA converter at a similar cost. Either of these requires that write-cycle endurance issues be managed, either by not storing frequently written files on the drive, or by using a Flash file system. Standard CompactFlash cards usually have write speeds of 7 to 15 megabytes per second while the more expensive upmarket cards claim speeds of up to 40 MB/s One of the first mainstream releases of SSD was the XO LaptopOLPC XO-1 The XO-1, previously known as the $100 Laptop or Children's Machine, is an inexpensive laptop computer intended ... built under the 'One Laptop Per ChildOne Laptop per Child The One Laptop per Child association is a U.S.... ' project. Mass production of these computers built for children in developing countries begun in December 2007. These machines use 1024 MiB SLC NAND flash as primary storage solution which is considered more suitable for the harsher than normal conditions they are expected to be used in. DellDell Dell Inc., an American computer-hardware company based in Round Rock, Texas, develops, manufactures, sells and supports a wi... has begun shipping ultra-portable laptops with SanDisk SSDs on April 26 2007. AsusASUS ASUSTeK Computer Inc. is a Taiwan-based company that produces motherboards, graphics cards, optical drives, PDAs, notebook c... released the Eee PCASUS Eee PC Photo= \| Developer = ASUSTeK Computer Inc.... subnotebookSubnotebook A subnotebook is an extremely small and lightweight portable computer, with all features of a standard laptop computer and r... on October 16 2007, and after a successful commercial start in 2007, expects to ship several million PCs in 2008, with 2, 4 or 8 gigabytes of flash memory. On January 31 2008 Apple Inc. released the MacBook AirMacBook Air The MacBook Air is a thin, lightweight, Apple Macintosh MacBook notebook computer featuring an optional solid-state hard dri... , a thin laptop with optional 64 GB SSD. The cost is $599 more for this option if configured in the Apple Store, as compared to that of an 80 GB 4200 RPM Hard Disk Drive. Another option - IBMIBM company_name = International Business Machines Corporation \|... Lenovo ThinkPadThinkPad ThinkPad is the brand name for a highly successful range of portable laptop and notebook computers originally designed and s... X300 with a 64Gbyte SSD - was announced by Lenovo in February 2008, and is currently available to consumers in some countries. On July 15, 2008, Advanced Media, Inc. /RiTEK USA first announced high performance / low cost MLC SSD -RiDATA Ultra-S Plus MLC series SSD. Capacity includes 32GB, 64GB and 128GB. Prices are $169 for 32GB, $257 for 64GB and $475 for 128GB. Product timeline Mtron announces flash memory solid-state drive, performing 100 MB/s Read, 80 MB/s Write, 72,000 Max IOPS in December 2005. On December 11, 2006, Advanced Media, Inc., manufacturer and marketer of the popular RIDATA brand of recordable CD and DVD media, electronic storage products, and digital media accessories, is set to add a non-volatile Flash Solid State Disk (SSD) storage medium to its RIDATA line. It is available in 16 GB and 32GB capacities. SanDiskSanDisk SanDisk Corporation, formerly SunDisk, is a US-based multi-national corporation which designs and markets flash memory... released a 32 GB 2.5-inch solid-state drive on March 13, 2007. The SSD SATA 5000 is being sold to computer manufacturers for $350. TaiwanTaiwan Taiwan is an island in East Asia, but the term "Taiwan" is also commonly used to collectively refer to the territories gove... ese A-DATAA-DATA A-DATA Technology is a Taiwanese memory manufacturer, founded on May, 2001 by Chairman and CEO Mr.... introduced at the Las VegasLas Vegas, Nevada Las Vegas is the most populous city in the state of Nevada, United States, and a major vacation, shopping, entertainment, a... CES 2007Consumer Electronics Show The International Consumer Electronics Show is a trade show held each January in Las Vegas, Nevada, and is sponsored by the... (January 2007) SSD drives at capacities of 32 GB, 64 GB (1.8" model) and 128 GB (2.5" model). It is expected to be commercially available by mid-2007. HyperdriveHyperdrive (storage) HyperDrive is a series of RAM disks manufactured by HyperOs Systems.... release the rev.4 designed to use 8 standard DDR ECC Registered memory modules on a native SATA and IDE interface. February 2007. On February 26, 2007, SMART Modular Technologies launched its first line of XceedUltra solid-state drives (SSDs). SMART's XceedUltra U100 is the industry's first SSD with a serial ATA (SATA) interface that achieves sustained read speeds of 100 MB/s and write speeds of 60 MB/s. Super Talent TechnologyFacts About Super Talent Technology Super Talent Technology is a San Jose, California based designer and manufacturer of DRAM and flash memory products for the ... announced a 3.5-inch 128 GB solid-state drive in April 2007. STEC, Inc.STEC, Inc. STEC, Inc. is a multinational company based in Santa Ana, California known for producing many forms of semiconductor me... has announced a 64 GB SSD that is only 9.5 mm thick, half the size of competing SSDs. On April 18, 2007, STEC announced 256 GB enterprise-level drives available immediately, and 512 GB drives available late 2007. LexarLexar Summary Lexar is an American manufacturer of various digital media and software based in Fremont, CA.... ExpressCard SSD is shipping in 4 GB, 8 GB, and 16 GB capacities, as of May 2007. PNY announces SSD lineup targeting OEM customers in 1.8" and 2.5" form-factors, PATA and SATA, capacities reaching 128 GB in May 24, 2007. Power Quotient International (PQI) Announces 256 GB SSD on 28 May, 2007. SanDiskSanDisk SanDisk Corporation, formerly SunDisk, is a US-based multi-national corporation which designs and markets flash memory... announces 64 GB SSDs of 1.8 UATA 5000 and 2.5 SATA 5000 on June 4, 2007. Violin Memory announces 1010 memory appliance on August 2, 2007. The DRAM version of their appliance is capable of supporting 504 GB of memory and the expected flash version will scale to a little over 5 TB. This 2U appliance is capable of over 3 Million random I/O per Second (IOPS). It is attached to a server through a 20 Gbit/s PCI Express connection (8 lanes) and has demonstrated 1400 MB/s read rate and 1000 MB/s write rate with 3µs latency. SMART On August 7, 2007, SMART Modular Technologies launched the XceedLite SATA SSD product line. Fusion-io announces ioDrive PCIe x4 NAND Flash Card 640 GB 100,000 IOPS 800 MB/s on September 24, 2007. Trident Space & Defense in October 2007 introduces highly rugged Triton Series Drives (shock, vibration, splash resistant) for military and industrial applications in a standard 2.5-inch form factor with 9.4 mm height. BiTMICRO launches SSD 3.5" with a capacity of 1.6 TB in November 2007. Will mostly be used for the army. SanDiskSanDisk SanDisk Corporation, formerly SunDisk, is a US-based multi-national corporation which designs and markets flash memory... released a 32 GB 1.8-inch solid-state drive on January 4, 2008. Texas Memory Systems achieved the highest number of IOPS (291,208.58) and the lowest Price Performance ($0.67/IOPS) when they took part in the Storage Performance Council's SPC-1 IOPS test in January 2008. ImationImation Imation Corporation is an American corporation spun off from 3M, with a worldwide presence that produces mainly data storag... announces Pro7000 SSD drive with 120 MB/s read and 90MB/s write performance [IOPS:81000/18000] and 0,1ms avg access time on March 10, 2008. ROMEDIA announced a 3.5-inch 128 GB solid-state drive on stock for sale on March 2008. Memoright announces SSD drives with 115 MB/s read and write performance confirmed on May 9, 2008. Samsung announces increase in capacity of its flash-based SSD line to 256 GB on May 25, 2008. This drive has reported speeds of 200MB/sec read and 160MB/sec write. Toshiba introduced a notebook that the vendor claims is the lightest laptop (2.4-pound) with a 128-GB Solid-State Drive, June 17, 2008. Fusion-io and Hewlett Packard announce working together to adapt the ioDrive flash SSD to provide acceleration in HP's BladeSystem and Enterprise Servers.June 18, 2008. On July 15, 2008, Advanced Media, Inc. / RITEK USA announced the world fastest MLC SSD. Ultr-S Plus SSD with 32GB, 64GB and 128GB. Read speed is up to 152MB/s based on Datamarck testing result, an independent site measuring performance of storage devices.. Compared to traditional hard drive, SSD is about 50%+ faster. External links - An article and an interview with Don Barnetson from Samsung about their technology puter Uses SSD")