Author - 扬加勒

ssd drives Solid state disk and mechanical hard disk storage principle

The basic working principle of a mechanical hard disk (HDD).ssd drives
When a mechanical hard drive needs to read or write data, it receives a command, the head moves to the appropriate position, and the platter rotates so that the data operation area is in the specified position.
The time required for these actions is the seek time and latency period, which take several milliseconds due to the need to move the device.
This is due to the read/write mechanism of the operating system:
Hard disk is divided into several areas as the most basic operating unit, the unit is called "sectors", when a new writing data, choose one or a few sectors for writing data, the position of these sectors are next to each other, they are logically continuous, in both the read and write the required time is short.
And here's the crux of the matter:
After all the data are not in the established forever there won't be changed, when previously written data modification, such as increasing the content and data volume increase, and next to the location of the original sectors have other data, these new data will be written to the other place to go, so we see in the operating system of a file, in the actual physical address is not continuous,
When the file is read again, the disk will have to do more work, and in the worst case, the head and platter will be moved and rotated many times, and the final working time will be doubled.
With the increase of storage capacity per unit area, we can enjoy higher capacity hard drives, but the speed of reading and writing data has not been much improved.
Because the key factors that determine seek time and latency period: head movement speed and disk rotation speed are close to the limit, further increase will bring other adverse factors: such as cost increase, noise, temperature increase and so on

1.Physical structure of the ssd drives

The system interface, power supply, and drive mode of SSDS are all the same as those of HDDS. The main changes are the constituent units and physical working mode.
The SSD internals include a PCB board, a main controller chip, a flash memory chip and, in some cases, a cache.
The most basic unit of an SSD is a Flash memory chip, called Nand Flash. It is a non-volatile memory chip that can write and erase data very fast by charging and dropping data.
Since signals are transmitted entirely through circuits during read and write operations, there is no movement of the head, rotation of the platter, etc., as in HDDS, which greatly reduces the processing time.
However, Nand Flash is also divided into several types. Currently, consumer SSDS and even many enterprise SSDS use MLC (multi-layer cell) Flash memory, which has a lower write performance than SLC (single-layer cell) Flash memory, and a shorter life span, but the price is much lower.
Even so, the current cost of SSD has not been reduced to the extent that everyone can accept, and the price is still the barrier affecting the further popularity of SSD.
An SSD is composed of multiple Nand flash flash memory particles, each of which can be considered as an independent storage unit, and the master controller makes a RAID parallel between them.
This means that SSD reads and writes are "multithreaded", and the work is not limited to one particle at a time. The master can split the data and write it to different particles at the same time, which is naturally faster.
This is one of the reasons why SSDS are fast.
Of course, what the master has to do is fa

2.The master controller of the ssd drives

SSD Flash memory also has a minimum operation unit. Compared with mechanical hard disks, Nand Flash has a special difference in that the minimum unit for write and erase operations is different. The minimum unit for write operations is 4KB, which is called "Page", while the minimum unit for erase operations is 512KB, which is called "Block".
That is, writing to a blank cell can be done on a page-by-page basis, but to delete the data, the entire block needs to be erased.
When the data in a block needs to be deleted, the data to be deleted will be marked rather than physically erased. Then when the data needs to be written in the same physical location again, the valid data will be retained, copied to the new block, and then the original block will be erased.
It sounds complicated, but to put it simply, the SSD write mechanism requires 1MB of data to be written. The actual operation volume may be larger than this. The specific amount depends on whether the main controller's algorithm is efficient, and the actual random write speed depends on whether the operation speed is fast enough.
Like HDDS, SSDS require logical addresses to be managed. However, the minimum operating system logical address unit is 512B, and the minimum SSD write unit is 4KB, which requires that, the chipset, and the main controller work in sequence.
In addition, the main controller and is responsible for the allocation of tasks, each flash chips all flash memory state monitoring, the management of each piece of data validation, etc., quite a lot of work and multifarious, and this is why in some of the new master ARM to use dual core processor, because master performance will directly affect the speed of the SSD.

3.Advantages of ssd drives

Fast read/write speed: The flash memory is used as the storage medium, and the read speed is higher than that of a mechanical hard disk.
Solid state drives are not used, and the seek time is almost zero.
The sustained write speed is amazing, and most SSD manufacturers will claim that their SSD sustained read/write speeds exceed 500/s!
Solid state drives are faster than just continuous read and write. Random read and write speed is the ultimate meaning of solid state drives, which is most directly reflected in most daily operations.
Also associated with this are extremely low access times, with the most common 7200RPM mechanical hard drives typically having seek times of 12-14, while solid state drives can easily reach 0.1ms or less.
Shockproof and smash resistant: Traditional hard disks are disk-shaped, and data is stored in the disk sector.
And solid-state drives is to use flash particles (i.e., mp3, U disk, etc), so there are no mechanical components inside SSD solid state hard drive, so even in the case of high-speed mobile even with flip tilt also won't affect the normal use, and in the case of collisions and shocks to minimize the possibility of loss.
Compared with traditional hard disks, solid state drives have absolute advantages.
Low power consumption: Solid state drives are lower than traditional hard disks.
No noise: Solid state drives have no mechanical motors and fans, and the noise level is 0 dB when working.
Flash-based solid-state drives consume less energy and generate less heat when operating (although higher-end or high-capacity devices consume more energy).
There are no mechanical moving parts inside, no mechanical failure, and not afraid of collision, impact, vibration.
Since solid-state drives use flash memory chips without mechanical components, they have the characteristics of low heat and fast heat dissipation.
Wide range of operating temperatures: Typical hard drives only work in the range of 5 to 55 degrees Celsius.
Most solid-state drives work from -10 to 70 degrees Celsius.
Solid-state disks are smaller and lighter than mechanical disks of the same capacity.
The interface specifications, definitions, functions, and usage methods of solid state drives are the same as those of common hard disks, and the product shape and size are the same as those of common hard disks.
Its operating temperature range is very wide (-40~85 degrees Celsius).
Lightweight: Solid-state drives are lighter in terms of weight, weighing 20-30 grams less than regular 1.8-inch hard drives.

ssd drives


【SSD SOLID State Disk】2023 How can I detect a hard disk fault

Simple to teach you to judge the hard drive failure problem

Disk faults can be classified into two types: SSD software faults and SSD hardware faults.
The classification of academic circles is complicated, not easy to remember( SSD SOLID State Disk), and not very practical.
I have many years of hard disk data recovery experience, just to the computer hard disk data recovery company, especially for many years encountered regular hard disk failure for a statistics and classification, many users such as hard disk failure can be according to the phenomenon corresponding to the initial judgment of hard disk failure.
1:Magnetic head damage Magnetic head damage is a common failure of hard disks, ( SSD )especially for IBM's later products.
High temperatures and cooling problems sent IBM, the founder of hard drives, to its grave.
The typical symptoms of head damage are failure to pass the self-test at startup, and the hard drive makes a regular "click, click" sound because it cannot find the path.
Some notebook hard disk sound will be relatively small, to listen to close to hear.
In this case, if the hard disk data is important, you should power off immediately, because after the head is damaged, the back swing of the head arm may scratch the disk and lead to countless data recovery.
At this time should find a strength of the data recovery company, do not get the computer city shop surface.

Now the domestic data recovery industry practitioners are uneven.

As we all know, the hard disk can only be disassembled and replaced in the pure room above 100 level.
If you disassemble a hard disk in a normal environment, the disk surface will become sticky and data cannot be recovered.
2:Motherboard damage If the hard disk motherboard burns out, the most common manifestation is that there is no response after the electricity.
Users can hold the hard drive in their hand and feel if it turns.
If it is a notebook hard disk is close to the hard disk to listen to whether there is a sound of rotation.
You can also see whether the components on the board have obvious burn marks.
If the damaged hard disk data is not important, you can go to the computer city to find a repair hard disk can be processed, if the data is important to consider, many repair hard disk will often repair the hard disk at the same time also lost data.
3.Hard disk Bad sector Hard disk bad sectors are common faults. Today's hard disks have a high speed and large capacity, which makes them more prone to bad sectors.
Users can install a fan for hard disks in common use, which is very effective against hard disk faults.
The symptom of a bad sector on a hard disk varies with the severity of the bad sector. For example, if the system starts slowly, a bad sector may occur on a system disk.
Or can enter the system, but inexplicably less partition or some partition can not be opened, or can open partition and some folders can not be opened.
These symptoms are typical of bad sectors on hard disks.
Some serious will make the system can not start normally, if mounted as a secondary disk or even make the primary disk system can not start.
Still have more serious, be BIOS seeks hard disk to want to seek along while.
At this time if the fault disk does not have important data, then get a small software low lattice, such as DM, MHDD and so on can be done, if serious may need professional tools such as PC3000.
If the faulty disk has important data, remember: Do not forcibly power on the faulty disk to replicate data, because bad sectors can easily spread.
Forcing electricity increases the number and density of bad roads.
It will increase the difficulty of data recovery and cost more.
Hard drive brands with fast bad sectors spread include Samsung, Western Digital, and IBM.
A bad track on a hard disk sometimes makes a sound, but it is not the same as a damaged head.
The sound is quieter than the damage of the magnetic head, and the hard disk indicator is steady on when a bad sector is detected.
Disk disk damage Disk damage is a common term in the industry. In fact, a disk cannot be identified and used due to an error in the firmware of the disk.
The firmware area refers to the most basic information about the hard drive stored in the negative area, such as the P list, G list, SMART table, disk size and so on.
After the disk is powered on, the magnetic head reads the information in the negative sector first. If the information in the negative sector is not read, the disk fails the self-test and an error is reported.
This type of failure typically involves a hard drive that would have reported an error in your F1 ignore or DEL CMOS setting after startup self-inspection.
Press DEL to enter the Settings, the detection of the hard disk will appear some wrong parameters, like The 40G thin disk of Maxtor will display N40P, and the capacity is generally 0, repair this kind of fault requires professional equipment.
Russia's PC3000 is the best at this and is widely used around the world.
MBR Damage The MBR is the master boot record of the hard disk, located on track 0 of the hard disk, and is very important basic information of the hard disk.
If the MBR is damaged, the hard drive can find the correct parameters in BIOS, but cannot be found in DOS or WINDOWS.
Many viruses can cause MBRS to be lost, as can bad hard drives or other human factors.
Partition table loss viruses, bad tracks, misoperations, mis-cloning, and misuse of one-click recovery (a new feature of many brands) can all lead to partition table loss.
If the entire partition table or a partition is lost due to misoperation, users should not do redundant operations to avoid overwriting data.
You can ask a professional company to restore data. If there is no important data, you can directly rebuild the partition.
The common disk faults are listed as follows. Although not all disk faults are listed, they are usually included.


hard drive or ssd1tb or ssd240gb or ssd512gb or disco ssd orssd sata 2.5 inch new/Refurbished 160GB/250GB/320GB/ 500GB 1TB 2TB HDD For Laptop/ Desktop

ssd hard disk vs hard drive  Ssd 120gb ssd 240gb ssd 512gb ssd 1tb ssd 2tb

ssd hard drive

are non-volatile computer storage devices that contain high-speed spinning disks or platters.It is the secondary storage device for permanently storing data, and random access memory (RAM) is the primary storage device.Nonvolatile means that data is retained when the computer is shut down.A hard disk drive is also called a hard drive .

HDD Mechanical hard disks and SOLID-state drives (SSDS)The hard drive is mounted inside the computer case and secured by the use of a bracket and screws to prevent it from shaking as it rotates.Typically it rotates at 5,400 to 15,000 RPM.Disks move at accelerated speeds, allowing immediate access to data.Most hard disks run on high-speed interfaces using serial ATA (SATA) or serial connection technology.An arm with a read/write head extends through the disc as it rotates.The arm writes new data to the disk and reads from it.Most hard drives use an enhanced Integrated Drive Electronics (EIDE),

which includes cables and connectors for the motherboard.All data is stored magnetically, allowing information to be saved when power is turned off.Hard disk drives require a read-only memory (ROM) controller board to indicate how, when and where read/write heads move.Hard drives stack disks on top of each other and rotate them in unison.

The read/write head is controlled by an actuator that magnetically reads and writes to the disk.The read/write head floats on a thin film of air above the platter.The two sides of the platter are used to store data.Each side or surface of a disk is called a head, and each head is divided into sectors and tracks.All tracks are the same distance from the center of the disk.Together they consist of a cylinder.Data is written to disk from the farthest track.Once the first cylinder is full, the read/write head moves inwards to the next cylinder.Hard disk drives are divided into one or more partitions, which can be further divided into logical drives or volumes.The master boot Record (MBR) is usually found at the beginning of the hard drive and contains a table of partition information.Each logical drive contains the boot record, the file allocation table (FAT), and the root directory of the FAT file system.hard drive

SSDS are Solid State Drives.HDDS are mechanical hard disks.The difference between:

Fast read and write speed of SOLID-state disk:

using flash memory as storage medium, the reading speed is faster than that of mechanical disk.
Solid-state drives do not use magnetic heads, and the seek time is almost zero.
The continuous write speed is so impressive that most SSD manufacturers will claim that their SSDS have sustained read/write speeds in excess of 500MB/s!

Solid state disks are shockproof and fall resistant:

Traditional hard disks are disk-type, and data is stored in the disk sector.
SSDS, on the other hand, are made of flash memory (mp3 players, USB flash drives, etc.), so there are no mechanical parts inside SSDS.This will not affect normal use even at high speed and even with tilting, and will minimize the possibility of data loss in the event of collision and vibration.hard drive

Solid-state drives have an absolute advantage over traditional hard drives.

Low power consumption: The power consumption of solid-state drives is lower than that of traditional hard drives.

solid-state drive no noise

solid-state drive has no mechanical motor and fan, the noise value is 0 db when working.
Flash-based SSDS consume less energy and heat while operating (although high-end or high-volume products consume more energy). There is no mechanical moving parts inside, no mechanical failure, and no collision, impact, vibration.
Solid-state drives use flash memory chips without mechanical components, so they have the characteristics of low heat generation and fast heat dissipation.hard drive

Low SSD life:

SOLID-state drives (SSDS) flash memory has a limited number of erase times, which is one of the reasons many people complain about their short life.
A complete erase of flash memory is called a P/E, so the lifetime of flash memory is measured in P/E units.

hard drive

hard drive or ssd1tb or ssd240gb or disco ssd orssd sata
The most basic computer memory, we often say in the computer hard disk C, D disk partition belongs to the hard drive

ssd1tb or ssd240gb or disco ssd Horizontal directional drilling

Horizontal directional drilling refers to the laying of a variety of underground public facilities (pipelines, cables, etc.) under the condition of no excavation of the surface of the ground.
It is widely used in water supply, electricity, telecommunications, natural gas, gas, oil and other pipeline laying construction, it is suitable for sand, clay, pebble and other ground conditions, most of China's non-hard rock areas can be constructed.

(HeatingDegreeDay) ssd1tb or ssd240gb or disco ssd

The heating index (HDD) is calculated as HDD=Max (65-T average temperature, 0). (HTC HDD phone) ssd hard drive

Touch screen: Capacitive screen, multi-touch camera Head: 10 megapixels Operating system: Windows Phone 7 Body MEMORY: 1GB ROM+1GB RAM Bluetooth Transmission:
Bluetooth 3.0GPS navigation: Memory card: MicroSD card.

ssd1tb or ssd240gb or disco ssd HDD Zipper brand ssd hard drive

Hangzhou dada zipper factory produces zipper brand.
The factory is an early professional production of zipper products base.
Investment scale, plant equipment, production capacity is the industry leader.hard drive

We provide a series of complete imported equipment such as dyeing, ribbon weaving, molding, stitching, and row microphone, producing "HDD" brand metal, nylon, resin zipper.
It is one of the manufacturers with the most complete varieties, sizes and models of zippers in China.
Professional clothing, bags, tents, bedding and other products supporting services.hard drive

ssd hard drive

hard drives vs memoria ddr4 ram ddr3 1333mhz 1600mhz 8gb 4gb 1600 mhz pin with ubdimm for pc desktop

The basic principle .memoria ddr4

DDR 400MHz that 400MHz refers to the memory bandwidth, is a converted value of the operating frequency.
The DDR 400MHz memory runs at a clock frequency of 200MHz. DDR can access data twice per clock cycle, so it is equivalent to running at a clock frequency of 400MHz (200MHz x 2).
The same algorithm, DDR2 533 memory, running frequency of 133MHz, each clock cycle can access four times of data, equivalent to 533MHz (133MHz×4).
Of course, the higher the number, the higher the frequency, the faster the memory must be.
DDR3, 4 memory has matured, several times faster than DDR2, DDR3 is currently used by mainstream motherboards, and DDR4 positioning is still in the mainstream above.

memoria ddr4

Current situation of the development of memoria ddr4

The standard specification for DDR4 memory is almost complete, and Samsung and Hynix have already completed their samples. However, DDR3 is still in its heyday, so it is not expected to arrive in a hurry.
The latest news is that DDR4 memory will first hit servers in 2014, and then the desktop in about a year and a half.
Haswell-ex, Intel's next generation enterprise server platform, will be the first to integrate DDR4 memory controllers.
Haswell-ex is part of the same family as Haswell that we've always envisioned, targeting large enterprise domains such as data centers with up to 16 cores, 64 cores for four routes.
DDR4 memory not only provides a significant increase in frequency (up to 4266MHz), but also features low voltage of 1.2V, better peer-to-peer protection, and error recovery. These large-scale applications in servers and enterprise centers will see immediate benefits.
As for the desktop, both 22nmHaswell and 14nm broadwell will use the same LGA1150 package interface, and memory controllers will naturally be limited to DDR3. DDR4 support is likely to wait until "Skylake", a new architecture for 14nm technology, in 2015.
AMD's 2016 cpus are compatible with DDR4 memory and will be used in the next generation of AM4 interfaces, namely Ryzen5 and above and A9 and above.
This pace is not fast, market research agencies have previously believed that DDR4 memory should be basically available by 2015.

upgrading too quickly is not a good thing, everyone can enjoy cheap DDR3 more secure.hard drives

And if you're worried that Haswell and Broadwell are going to lose out on memory performance, don't worry. A DDR3 is sure to become more and more common, with new features such as ultra-low latency internal memory controllers, flush capabilities, floating point peak emittance, FMA arithmetic, and four-level caching.
All contribute to better memory performance.
Interface of a memory module. Common memory modules are as follows:
Single-row in-line Memory modules (SIMM) and dual-row in-line memory modules (DIMMs).
SIMM memory modules are classified into 30 lines and 72 lines.
Compared with SIMM memory modules, DIMM pins increase to 168 lines.
Dimms can be used in a single or mixed manner. Simms must be used in pairs.
According to the way memory works, memory has FPA EDO DRAM and SDRAM (synchronous dynamic RAM) and other forms.
FPA (FAST PAGE MODE) RAM: This is common memory in older computer systems that transmits data every three clock pulse cycles.
EDO (EXTENDED DATA OUT) RAM: EDO memory cancels the time interval between the motherboard and memory cycles. It outputs DATA once every two clock pulse cycles, greatly shortening the access time and increasing the storage speed by 30% EDO memory has been replaced by SDRAMS (SYSNECRONOUS) DRAM Synchronous Dynamic Random access Memory: SDRAM is 168 bits, which is currently used by PENTIUM models and above.
SDRAM locks THE CPU and RAM together through an identical clock so that the CPU and RAM can share a clock cycle and work synchronously at the same speed. The rising edge of each clock pulse starts to transfer data, which is 50% faster than EDO memory.

DDR (DOUBLE DATA RAGE) RAM: memoria ddr4/ hard drives

The next generation of SDRAM, which allows DATA to be transmitted on the rising and falling edges of clock pulses, thus doubling the speed of SDRAM without increasing the clock frequency.
RDRAM (RAMBUS DRAM) memory bus dynamic random access memory;
RDRAM is a new TYPE of DRAM developed by RAMBUS corporation with system bandwidth, chip to chip interface design, which can transfer data over a very high frequency range over a simple bus.
He uses both low-voltage signals to transmit data on both sides of a high-speed synchronized clock pulse.
INTEL will add support for RDRAM to its 820 chipset.
Because the price of such memory is too expensive, it is no longer seen on PCS.
DDR2 (Double Data Rate 2) SDRAM is a new generation of memory technology standard developed by JEDEC (Joint Committee for Electronic Equipment Engineering). The biggest difference between IT and the previous generation OF DDR memory technology standard is that although the basic way of Data transmission is adopted at the same time when the clock rises/falls,
DDR2 memory modules, however, provide four bits of data read prefetch, twice that of the previous generation DDR memory.
In other words, DDR2 memory can read/write data at four times the speed of an external bus per clock, and can run at four times the speed of an internal control bus.
In addition, as the DDR2 standard stipulates that all DDR2 memory is packaged in FBGA format, FBGA provides better electrical performance and heat dissipation, which provides a solid foundation for the stable operation and future frequency development of DDR2 memory.
Recalling the development process of DDR, from the first generation of DDR200 applied to personal computers through DDR266, DDR333 to today's dual channel DDR400 technology, the development of the first generation of DDR has come to the limit of technology, it is difficult to improve the working speed of memory through conventional methods;
With the development of Intel's latest processor technology, the front-end bus has higher requirements on memory bandwidth. DDR2 memory with higher and more stable running frequency will become the trend.

hard drives

2.DDR (generation DDR)
3.DDRII (second generation of DDR)
Several kinds of memory gold finger is different, the working voltage is different.
It's not universal. It doesn't slot in.
SDR belongs to the eliminated category, there are no new products, only second-hand.
DDRII is gradually replacing DDR. At present, DDRII with the same capacity has better performance than DDR, but its price is lower than DDR.
DDR faces elimination.
DDRIII has the best performance, is developing and currently costs a lot more than others.
The current mainstream is DDRII, and in a few years it will be DDRIII.


ssd hard disk vs hard drive  Ssd 120gb ssd 240gb ssd 512gb ssd 1tb ssd 2tb

1tb ssd drive

hard drives

Based on this latitude, common SSD can be classified into three types: SATA, M.2, and PCIE.

The conclusions below are based on the control variable (type of interface), and all other conditions are equal by default.

SATA 2.5-inch solid-state disks have the same interface as the current mechanical disks on the market. They both have a power supply interface and a SATA3.0 data interface.

ssd hard disk  Ssd 256gb

This type of SSD is also the early form of SSD.ssd hard disk

SSD with the M.2 interface are the favorite products of computer manufacturers in recent years. When used, they can be inserted directly into the motherboard interface and fixed with screws.

Both size and installation convenience are better than traditional 2.5-inch SOLID-state drives.

It should be noted that the M.2 interface supports both SATA and PCIE channels. If it uses the SATA bus on the mainboard, its performance is not significantly different from that of the traditional SOLID-state disk, while the M.2 interface SSD that uses the PCIE bus on the mainboard is the product with better performance.

The IDE protocol is a very old transport protocol for mechanical hard disks, and there is no need to discuss it.

ALTHOUGH the AHCI protocol performs better, it is only for mechanical hard disks and was born.

 SATA protocol is the most widely used transmission protocol, faster transmission speed, high execution efficiency, but also support hot swap, currently on the market most of the hard disk or use SATA protocol, SATA 3.X has basically met all the needs of the civil market.

 NVMe is a transport protocol specially developed for flash memory products. It is the optimal solution of SSD transport protocol, which can give full play to SSD performance and reduce latency.

Is the preferred SSD protocol for the M.2 interface.ssd hard disk

Flash-based SOLID-state drives (SSDS) are the main category of SSDS. Their internal structure is very simple. The main body of SSDS is actually a PCB board, and the basic accessories of this PCB board are the control chip, the cache chip (some low-end hard drives have no cache chip) and the flash chip for storing data.

Main control chip.ssd hard disk

Common SSDS in the market include LSISandForce, Indilinx, JMicron, Marvell, Phison, Sandisk, Goldendisk, Samsung and Intel and other master chips.

The master chip is the brain of the SSD. Its function is to reasonably allocate the load of data on each flash chip, and to undertake the whole data transfer and connect the flash chip with the external SATA interface.

The ability difference between different master is very big, in the data processing ability, algorithm, read and write control of the flash chip will be very different, which directly leads to the performance gap of SSD products up to several times.

ssd hard disk.Cache particles

Next to the master chip is the cache particle. Like traditional hard drives, SSDS need high-speed cache chips to assist the master chip in data processing.

It is important to note that there are some low-cost SOLID-state drive solutions that do not use this cache chip to save costs, which can have a certain impact on the performance, especially the read and write performance and service life of small files.

ssd hard disk.Flash memory chips

Except for the main control chip and the cache chip, most of the other positions on the PCB are NAND Flash chips.

NAND Flash memory chips are divided into SLC (single-level Cell) [7], MLC (multi-level Cell) [7], TLC (Trinary Level Cell),

Three-layer Cell) [7] and QLC (Quad-level Cell, four-layer Cell).

Another eMLC (Enterprise Multi-level Cell) is an "enhanced" version of MLC NAND flash memory, which to some extent Bridges the performance and durability gap between SLC and MLC.