For each hard disks installed in the system, Hard Disk Sentinel maintains a log. The degradations of the data field of the most important S.M.A.R.T. attributes are saved into this log. These attributes are:
5: Reallocated Sectors Count.
10: Spin Retry Count.
196: Reallocation Event Count.
197: Current Pending Sector Count.
198: Off-Line Uncorrectable Sector Count.
199: Ultra ATA CRC Error Count (data transfer errors).
If a hard disk does not respond to the query of Hard Disk Sentinel for a longer time, it is also logged (if this function is enabled on the advanced options page).
All entries have the exact date and time, the attribute identifier and the previous and new raw values of the attribute. It is possible that two or more attributes have changed since the previous detection (especially if Hard Disk Sentinel is started only occassionally), creating two or more log entries at the same time.
It is possible to configure the application to send/make alert if a new entry is added to the log. This way if any new problem is detected by Hard Disk Sentinel (which may change the disk condition), it can alert the user about it. This feature is available only in the registered version.
It is possible to disable some attributes on the S.M.A.R.T. page of the disk, by using the option under the "Enable" column. The changes of disabled attributes will not be saved to the log (they will not generate alerts) and they do not affect the disk health value.
Note: The current version of the log stores the most recent 50 problems only. After this, the oldest problems are discarded.
Note: The above information reflects the original design of Hard Disk Sentinel. Depending on the actual disk, device connection/model, different attributes and their change/degradation may be also reported on the Log page, as different devices (hard disks and SSDs) may have further (or completely different) attributes which are important to monitor for changes.