Test Principle and Main Points of SSD Power - Down Protection

Prelude

Strong state hard drive If you should utilize FTL to do the intelligent location and the physical location between the transformation, if the SSD read, compose, erase and other ordinary work on account of irregular shut down, may cause mapping table in view of past the point where it is possible to refresh and lost There is a shortcoming that the SSD can not be perceived by the framework.

Simultaneously, so as to improve peruse and compose execution, for the most part use SDRAM to do the store, if the way toward perusing and recording experienced irregular force, SDRAM information might be past the point where it is possible to compose Nand Flash information misfortune, or update the mapping table past the point where it is possible to compose Nand Flash The mapping table is absent.

Unusual force disappointment brought about by the wonder

SSD irregular force disappointment for the most part there are three sorts of disappointment marvel:

1, SSD can not recreate the framework distinguishing proof, the need to modify the mapping table or by basic and rough approach to re-creation can be utilized;

2, commonly after force disappointment, SSD there are a great deal of "new awful square";

The instrument behind the new terrible square is that when the SSD peruses, composes, or eradicates ineffectively, it will be distinguished as an awful square. Obviously, these squares are not so much terrible squares, since they are strange Power disappointment brought about by an inappropriate judgment.

3, SDRAM information misfortune;

Regular shut down security instrument

Each shut down insurance component to comprehend unique, diverse for the client, the assurance instrument is totally extraordinary, for the most part there will be the accompanying two practices:

1, spare all the information in SDRAM

Strange shut down, SDRAM all information must be completely composed to Nand Flash, all in all, SDRAM limit is set to 1000% of the measure of SSD uncovered limit, for little limit SSD, SDRAM need to compose Nand Flash information Relatively little, through the super capacitor or tantalum capacitor can keep on composing information. Notwithstanding, on the off chance that the SSD limit is sufficiently huge, for instance: 8TB, at that point, SDRAM need to compose Nand Flash information will be exceptionally huge, if still depend on super capacitor or tantalum capacitor to do control supply, will unavoidably confront the accompanying three precarious issue:

a, the requirement for more tantalum capacitor particles to do the security, in the real building practice, this is an intense test, the architects face the thickness, the standard size breaking point, PCB territory isn't sufficient to utilize;

b, regardless of whether there is sufficient capacitance to do the insurance, when the usage of the "restart", the SSD won't start appropriately, you should initially close down for quite a while before restarting, on the grounds that: SSD need to put all the tantalum capacitor after force Identified;

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c, when the utilization of a couple of years after the tantalum capacitor or super capacitor subsequent to maturing, when the tantalum capacitor power supply can not accomplish the underlying plan target esteem, the client despite everything has information misfortune after influence misfortune or SSD can not distinguish the potential dangers, on the off chance that the underlying structure That is, to do excess capacitors, at that point, will come back to the issue "b" demise cycle.

It is satisfying that the issues of b and c are ideal answers for take care of these prickly issues just need the designers enough psyche and experience as it were.

2, just spare the SDRAM client information, without sparing the mapping table

This will decrease the utilization of SDRAM and the utilization of tantalum capacitors, "don't spare the mapping table" doesn't imply that the mapping table is lost, simply don't spare the last information compose update map, when the SSD re-power, Looking for the last mapping table to spare the new information kept in touch with re-assemble the mapping table, the disadvantages of this methodology isn't sufficient instrument to set the sensible, at that point revamp the mapping table will be longer, SSD sets aside some effort to typical access to ordinary

For controllers without SDRAM plan, all information is composed legitimately to Nand Flash. At the point when information is lost, the information that isn't composed to Nand Flash will be come back to the host. On the off chance that no extra information should be spared, High unwavering quality prerequisites of the application, no SDRAM configuration is above all else, its agent is a German modern brand ace, its solitary disadvantage is that the presentation isn't adequate, truth be told, numerous applications and the requirement for the best, and Is "sufficient" execution.

Test strategies and standards

Explicit test, SSD need as a framework plate and as a circle from the two instances of testing, so the fundamental circle and do from the plate test technique is the main contrast is that the principle plate need to test the PC to control off the machine, and from the circle no one but SSD can be on the force off.

a, separately, of the SSD as a clear plate, information is written in the 25% and half when composing information, the compose information for 85% and 3000, individually, the anomalous shut down 100% test compose information, each down And the force on time interim of 3 seconds;

The rule of composing diverse limit information to the plate is: When the SSD compose a specific measure of information, the foundation started to trash assortment, trash assortment implies that the movement of information, information relocation implies that the mapping table updates, right now Abnormal force disappointment is generally an issue.

b, when the typical compose information, the SSD irregular shut down

c, when the information is erased when the irregular shut down

In the windows, erase the information additionally need to perform eight activities, and the foundation of a similar archive, the mapping table likewise need to refresh.