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SLC Cache
Write amplification (WA) is an undesirable phenomenon associated with flash memory and solid-state drives (SSDs) where the actual amount of information physically written to the storage media is a multiple of the logical amount intended to be written. Because flash memory must be erased before it can be rewritten, with much coarser granularity of the erase operation when compared to the write operation, the process to perform these operations results in moving (or rewriting) user data and metadata more than once. Thus, rewriting some data requires an already-used-portion of flash to be read, updated, and written to a new location, together with initially erasing the new location if it was previously used. Due to the way flash works, much larger portions of flash must be erased and rewritten than actually required by the amount of new data. This multiplying effect increases the number of writes required over the life of the SSD, which shortens the time it can operate reliably. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Write Amplification On SSD
Writing is the act of creating a persistent representation of language. A writing system includes a particular set of symbols called a ''script'', as well as the rules by which they encode a particular spoken language. Every written language arises from a corresponding spoken language; while the use of language is universal across human societies, most spoken languages are not written. Writing is a cognitive and social activity involving neuropsychological and Writing process, physical processes. The outcome of this activity, also called ''writing'' (or a ''Text (literary theory), text'') is a series of Handwriting, physically inscribed, Printing press, mechanically transferred, or Digital data, digitally represented symbols. Reading is the corresponding process of interpreting a written text, with the interpreter referred to as a ''reader''. In general, writing systems do not constitute languages in and of themselves, but rather a means of encoding language such that it can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash Translation Layer
A flash memory controller (or flash controller) manages data stored on flash memory (usually NAND flash) and communicates with a computer or electronic device. Flash memory controllers can be designed for operating in low duty-cycle environments like memory cards, or other similar media for use in PDAs, mobile phones, etc. USB flash drives use flash memory controllers designed to communicate with personal computers through the USB port at a low duty-cycle. Flash controllers can also be designed for higher duty-cycle environments like solid-state drives (SSDs) used as data storage for laptop computer systems up to mission-critical enterprise storage arrays. Initial setup After a flash storage device is initially manufactured, the flash controller is first used to format the flash memory. This ensures the device is operating properly, it maps out bad flash memory cells, and it allocates spare cells to be substituted for future failed cells. Some part of the spare cells is also u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garbage Collection
Waste collection is a part of the process of waste management. It is the transfer of solid waste from the point of use and disposal to the point of treatment or landfill. Waste collection also includes the curbside collection of recyclable materials that technically are not waste, as part of a municipal landfill diversion program. Household waste Household waste in economically developed countries will generally be left in waste containers or recycling bins prior to collection by a waste collector using a waste collection vehicle. Waste collection barges are used in some towns, for example in Venice, Italy. However, in many developing countries, such as Mexico and Egypt, waste left in bins or bags at the side of the road will not be removed unless residents interact with the waste collectors. Mexico City residents must haul their trash to a waste collection vehicle which makes frequent stops around each neighborhood. The waste collectors will indicate their readiness by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multi-level Cell
In electronics, a multi-level cell (MLC) is a memory cell (computing), memory cell capable of storing more than a single bit of information, compared to a single-level cell (SLC), which can store only one bit per memory cell. A memory cell typically consists of a single floating-gate MOSFET (metal–oxide–semiconductor field-effect transistor), thus multi-level cells reduce the number of MOSFETs required to store the same amount of data as single-level cells. Triple-level cells (TLC) and quad-level cells (QLC) are versions of MLC memory, which can store three and four bits per cell respectively. The name "''multi''-level cell" is sometimes used specifically to refer to the "''two''-level cell". Overall, the memories are named as follows: # Single-level cell or SLC (1 bit per cell) # Multi-level cell or MLC (2 bits per cell), alternatively double-level cell or DLC # Triple-level cell or TLC (3 bits per cell) or 3-Bit MLC # Quad-level cell or QLC (4 bits per cell) # Penta-level ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Deduplication
In computing, data deduplication is a technique for eliminating duplicate copies of repeating data. Successful implementation of the technique can improve storage utilization, which may in turn lower capital expenditure by reducing the overall amount of storage media required to meet storage capacity needs. It can also be applied to network data transfers to reduce the number of bytes that must be sent. The deduplication process requires comparison of data 'chunks' (also known as 'byte patterns') which are unique, contiguous blocks of data. These chunks are identified and stored during a process of analysis, and compared to other chunks within existing data. Whenever a match occurs, the redundant chunk is replaced with a small reference that points to the stored chunk. Given that the same byte pattern may occur dozens, hundreds, or even thousands of times (the match frequency is dependent on the chunk size), the amount of data that must be stored or transferred can be greatly reduce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoned Storage
In urban planning, zoning is a method in which a municipality or other tier of government divides land into land-use "zones", each of which has a set of regulations for new development that differs from other zones. Zones may be defined for a single use (e.g. residential, industrial), they may combine several compatible activities by use, or in the case of form-based zoning, the differing regulations may govern the density, size and shape of allowed buildings whatever their use. The planning rules for each zone determine whether planning permission for a given development may be granted. Zoning may specify a variety of outright and conditional uses of land. It may indicate the size and dimensions of lots that land may be subdivided into, or the form and scale of buildings. These guidelines are set in order to guide urban growth and development. Zoning is the most common regulatory urban planning method used by local governments in developed countries. Exceptions include the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trim (computing)
A trim command (known as TRIM in the ATA command set, and UNMAP in the SCSI command set) allows an operating system to inform a solid-state drive (SSD) which blocks of data are no longer considered to be "in use" and therefore can be erased internally. Trim was introduced soon after SSDs were introduced. Because low-level operation of SSDs differs significantly from hard drives, the conventional manner in which operating systems handle storage operations—such as deletions and formatting—resulted in unanticipated progressive performance degradation of write operations on SSDs. Trimming enables the SSD to more efficiently handle garbage collection, which would otherwise slow future write operations to the involved blocks.Shimpi, Anand Lal. (18 March 2009). p. 10. TRIM is an ATA command (Advanced Technology Attachment Command) that allows an OS to inform SSD about the blocks of data no longer in use. The SSD then deletes such blocks of data to make a way for newer blocks of da ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Write Amplification
Write amplification (WA) is an undesirable phenomenon associated with flash memory and solid-state drives (SSDs) where the actual amount of information physically written to the storage media is a multiple of the logical amount intended to be written. Because flash memory must be erased before it can be rewritten, with much coarser granularity of the erase operation when compared to the write operation, the process to perform these operations results in moving (or rewriting) user data and metadata more than once. Thus, rewriting some data requires an already-used-portion of flash to be read, updated, and written to a new location, together with initially erasing the new location if it was previously used. Due to the way flash works, much larger portions of flash must be erased and rewritten than actually required by the amount of new data. This multiplying effect increases the number of writes required over the life of the SSD, which shortens the time it can operate reliably. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-Monitoring, Analysis, And Reporting Technology
Self-Monitoring, Analysis, and Reporting Technology (backronym S.M.A.R.T. or SMART) is a monitoring system included in computer hard disk drives (HDDs) and solid-state drives (SSDs). Its primary function is to detect and report various indicators of drive reliability, or how long a drive can function while 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 action can be taken to prevent data loss, and the failing drive can be replaced and no data is lost. Background Hard disk and other storage drives are subject to failures (see hard disk drive failure) which can be classified into two basic classes: * ''Predictable failures'' which result from slow processes such as mechanical wear and gradual degradation of storage surfaces. Monitoring can determine when such failures are becoming more likely. * ''Unpredictable failures'' which occur without warning due to anyt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
