Flash Features & Functions


The Advanced LDPC ECC Engine is an error-correcting mechanism that is far superior than its predecessors. As the Flash controller has evolved, it has become more complex, and thus error correction needs to be more precise on each minute portion of data as well. LDPC can correct more errors per pages than before, thus sustaining the lifespan of the SSD. 
 
DEVSLP, short for device sleep, is a feature in SATA devices that reduces power consumption by setting the device to a “low power” (or sleep) mode. This device sleep state consumes less power than the traditional low power mode, which needs to remain powered to receive the wake-up command.
 
Dynamic thermal throttling is a temperature-adjustment mechanism that prevents the SSD from overheating. When the disk reaches a maximum temperature threshold, this feature will automatically adjust performance to drop to the extent necessary for recovering a stable temperature to cool down the device's temperature. Once the temperature decreases to the predetermined acceptable levels, transfer speed will rise back to its optimum performance level. 
 
End-to-End Data Protection is a comprehensive protection that covers the entire pathway for data transmission from the host computer to the SSD and back. Having multiple points of protections ensures that data integrity is preserved, especially since the protection detects and corrects any errors that may occur in these long transmission journeys.

 


Write Protection is a function that, when switched on, makes data read-only and thus prevents any tampering, leaks or malicious use by unauthorized third parties. With the function switched on, the NAND Flash is protected from any action, thus protecting the sensitive data from being overwritten or deleted.
 
Secure Erase is a function that thoroughly erases the data stored in the SSD and makes it irretrievable. Once the data is erased, the SSD remains intact and can be reused. 

 


Bad Block Management is a built-in management program that detects and tags bad memory blocks within the SSD, so that no data is written into them. Once marked, data in these bad blocks will be transferred to the good blocks, thus preserving the data integrity and overall performance and durability of the SSD. 
 
Over-provisioning is a function that sets aside space for the SSD's provisional use. These free blocks allow the SSD to operate at normal speed while other functions such as wear-leveling or garbage collection is taking place. The blocks also serve as replacements for bad blocks that may be detected during bad block management.  
 
Page mapping is an advanced technology that writes in data at a smaller unit than the original block-based mapping. Since a page is smaller than a block, mapping based on pages increases speed and accuracy and reduces the wear on the NAND Flash. Overall, this preserves and lengthens the life span of the SSD.
 
S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) is a diagnostic system that is convenient in gauging the health of HDDs and SSDs. The technology is built-in and actively monitors a set of data related to the drive's reliability and durability. S.M.A.R.T. provides users with an accurate idea of when the drive may need to be replaced.
 
TRIM support is a command function that allows the Operating System to inform the SSD controller of the locations of data that are no longer in use and can be wiped internally. Without it, these blocks of data will not be deleted but rather be marked as “not in use.” Once the TRIM command is given, the controller wipes these blocks, and frees up space. 
 
Write Amplification Factor (WAF) is the numerical value that denotes the number of writes actually taking place in relation to the number issued by the controller. To reduce WAF, the NAND controller writes in the data in a sequential order to reduce the movement within the Flash module later on when the data needs to be erased. With fewer movements, the SSD sustains less wear and thus has a longer lifespan.
 
Wear leveling is a technical process with which an SSD can prolong its longevity. This mechanism is particularly of use for non-SLC SSDs that store more than one bit per cell which causes increased wear. With wear leveling, the flash controller distributes all P/E cycles evenly to each block, making sure that they reach their P/E threshold at the same time as opposed to prematurely. 

 


Intelligent SLC Caching is a way of storing data primarily used in TLC SSD. The SSDs that employ such a feature uses part of the NAND flash for SLC caching, meaning that they save only 1 bit of data in each cell. This mechanism speeds up the I/O speed of the SSDs, and thus they can write data at higher speeds while consuming less power and sustaining less wear.
 
IOPS (Inputs/Outputs per Second) is an important indicator of the performance for a hard disk driver or solid-state drive. The IOPS indicates how many input and output (or read and write, respectively) operations the storage device can complete within a second. While it cannot guarantee real-world performance, the IOPS is a benchmark for the speed and capacity of the storage device.