Data storage system having data locking and unlocking functions and method therefor

1. A data storage system having data locking and unlocking functions, comprising:

a hardware processor;

a storage device, having a file system, wherein the file system comprises a plurality of folders; and

a processing circuit, coupled to the storage device, the processing circuit includes:

a blocking circuit, configured to lock the folders when a used capacity of the storage device is equal to or greater than a first threshold, and prevent the locked folders from being unlocked when the used capacity is greater than or equal to a second threshold, wherein the second threshold is greater than the first threshold, and unlock the locked folders according to a first unlock signal when the used capacity is less than the first threshold; and

a trigger circuit, configured to receive a second unlock signal, and unlock the locked folders according to the second unlock signal when the used capacity is between the first threshold and the second threshold;

wherein after the trigger circuit unlocks the locked folders, when the used capacity of the storage device equal to or greater than the second threshold, the blocking circuit re-locks the folders and prevents the re-locked folders from being unlocked.

2. The data storage system having data locking and unlocking functions according to claim 1 , wherein the first threshold is a default value at a first time point, and is an adjusted value at a second time point later than the first time point, and the adjusted value is greater than the default value and less than the second threshold; when the used capacity is equal to or greater than the default value, the blocking circuit locks the folders; when the used capacity is less than the adjusted value, the blocking circuit unlocks the locked folders according to the first unlock signal.

3. The data storage system having data locking and unlocking functions according to claim 2 , wherein the second unlock signal is from an input and output device; the data storage system further comprises a monitoring circuit, configured to monitor the used capacity; when the used capacity is less than the first threshold, the monitoring circuit generates the first unlock signal.

4. The data storage system having data locking and unlocking functions according to claim 1 further comprises a display device, configured to selectively display a first message, a second message, or a third message according to the used capacity; when the used capacity is greater than the second threshold, the display device displays the first message; when the used capacity is between the first threshold and the second threshold, the display device displays the second message; and when the used capacity is less than the first threshold, the display device displays the third message.

5. The data storage system having data locking and unlocking functions according to claim 1 , wherein the blocking circuit comprises a timer, configured to perform timing to generate a count value when the used capacity is between the first threshold and the second threshold and when the used capacity is greater than the second threshold; when the count value reaches a preset time at least once and the folders are not locked, the blocking circuit locks the folders and prevents the trigger circuit from unlocking the locked folders according to the second unlock signal.

6. The data storage system having data locking and unlocking functions according to claim 5 , wherein the folders are stored in a physical block of the storage device; the data storage system further comprises a file deletion circuit; when the count value reaches the preset time at least once, the file deletion circuit deletes the locked folders after the locked folders are copied into another physical block.

7. A data locking and unlocking method, comprising:

a processing circuit locking a plurality of folders of the storage device when a used capacity of a storage device is equal to or greater than a first threshold;

the processing circuit preventing the folders from being unlocked when the used capacity is greater than or equal to a second threshold, wherein the second threshold is greater than the first threshold;

the processing circuit unlocking the locked folders according to a first unlock signal when the used capacity is less than the first threshold;

the processing circuit unlocking the locked folders according to a second unlock signal when the used capacity is between the first threshold and the second threshold; and

after a trigger circuit unlocks the locked folders according to the second unlock signal, when the used capacity of the storage device equal to or greater than the second threshold, the processing circuit re-locking the folders and preventing the re-locked folders from being unlocked.

8. The data locking and unlocking method according to claim 7 further comprises: after the used capacity is equal to or greater than the first threshold, adjusting the first threshold, so that the used capacity is less than the adjusted first threshold and less than the second threshold.

9. The data locking and unlocking method according to claim 8 , wherein the step of unlocking the locked folders according to the second unlock signal is to unlock the locked folders according to the second unlock signal from an input and output device; the step of unlocking the locked folders according to the first unlock signal comprises:

monitoring the used capacity; and

generating the first unlock signal when the used capacity is less than the first threshold value.

10. The data locking and unlocking method according to claim 7 further comprises:

displaying a first message when the used capacity is greater than the second threshold;

displaying a second message when the used capacity is between the first threshold and the second threshold; and

displaying a third message when the used capacity is less than the first threshold.

11. The data locking and unlocking method according to claim 7 , wherein the step of locking the folders when the used capacity is equal to or greater than the first threshold comprises:

performing timing to generate a count value when the used capacity is between the first threshold and the second threshold and when the used capacity is greater than the second threshold; and

when the count value reaches a preset time at least once and the folders are not locked, locking the folders and preventing the locked folders from being unlocked.

12. The data locking and unlocking method according to claim 11 , wherein the folders are stored in a physical block of the storage device; the step of locking the folders when the used capacity is equal to or greater than the first threshold further comprises: when the count value reaches the preset time at least once, deleting the locked folders after the locked folders are copied into another physical block.