![]() The data value of Power Cycle Count means the power on/off cycle count for the SSD, it is usually just a few times for a new drive. This parameter shows the accumulated power on time of the SSD, it is supposed to be 0 for a new SSD drive, while in fact the SSD manufacturers have already used for several or dozens of hundreds of hours during the testing process, it is just the parameter is resumed to be 0 by re-implanting firmware after the tests. Usually, the time of all three states of work, idle and sleep are counted, some SSD solutions exclude the time of sleep by enabling some power management functions. The unit of measurement is generally an hour, it could be a minute or second, which is defined by SSD manufacturer. This index indicates the initial health condition of NAND Flash, the data values include correctable and uncorrectable errors. The S.M.A.R.T of SSD is not completely the same as that of HDD, those common testing software which can be got from the internet are designed based on HDD, SSD manufacturers usually make their own decisions to set S.M.A.R.T attributes according to the characteristics of NAND Flash. The S.M.A.R.T information of SSD is saved in specific areas assigned by firmware, it could be in the area of OP (Over Provisioning) or possibly any area chosen by the firmware engineers, or saved with an independent table. Through the years of continuous improvements by HDD manufacturers, some S.M.A.R.T standards are formed, however, for SSD, most S.M.A.R.T parameters are user-defined, thus the parameters provided by every manufacturer may be different, but generally, they refer to HDD S.M.A.R.T to set them. SSD controller manufacturers can also provide corresponding tools: S.M.A.R.T information of the SSD can be obtained through some common testing software: ![]() ![]() The SSD health condition can be monitored and the parameter values can be fed back to the monitoring software or operating systems, in fact, most parameters are meaningful only for SSD engineers, the end users just need to focus on some key indexes, such as New Bad Blocks, Remaining Life and Erase Count, etc. can be read from its name with the function of fault alarm. This is seemingly not critical, however, it may bring serious consequences of losing data packets if the SSD is applied in those critical domains like data acquisition, while of course this bug is correctable, first let us look at the screenshot:Īs the short for Self-Monitoring Analysis And Reporting Technology, S.M.A.R.T. The S.M.A.R.T command was confirmed as the cause after the study. Before writing this article, we found that performance degradation occasionally happened to the SSD during the testing process.
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