The three columns together tell you the status of an attribute.

"current" means the current value. Usually it is at 100 when everything is ok. Higher values often mean that the attribute has never been updated (implies 100).

The column "worst" tells you what worst value SMART has ever assigned to this attribute.

"threshold" is the absolute health threshold and indicates the value at/below which SMART consideres the attribute a failure. Most attributes that have a zero threshold are not critical. When they decrease, it just means that you drive gets older. Other attributes have thresholds greater than 0 and are often critical.

The uncorrectable sector count is an important attribute that very often indicates a total failure. Watch this attribute very closely. If it increments too rapidly, it is better to look for a replacement drive. SMART is not always implemented honestly, in my opinion. 100% health with 8 uncorrectable sectors is such a case. Try to do a surface scan, but before you do such an operation with high I/O load, make a backup.

As concerns your first question, the three columns together tell you the status of an attribute.

Column "current" means the current value. Usually it is at 100 when everything is ok. Higher values often mean that the attribute has never been updated (implies 100).

The column "worst" tells you what worst value SMART has ever assigned to this attribute.

"threshold" is the absolute health threshold and indicates the value at/below which SMART consideres the attribute a failure. Most attributes that have a zero threshold are not critical. When they decrease, it just means that you drive gets older. Other attributes have thresholds greater than 0 and are often critical.

As concerns your second question, the uncorrectable sector count is an important attribute that very often indicates an imminent total failure. Watch this attribute very closely. If it increments too rapidly, it is better to look for a replacement drive. SMART is not always implemented honestly from what I've seen. 100% health with 8 uncorrectable sectors is such a case. Try to do a surface scan if you would like to save/check the drive, but before you do such an operation with high I/O load, make a backup.

The three columns together tell you the status of an attribute.

"current" means the current value. Usually it is at 100 when everything is ok. Higher values often mean that the attribute has never been updated (implies 100).

The column "worst" tells you what worst value SMART has ever assigned to this attribute.

"threshold" is the absolute health threshold and indicates the value at/below which SMART consideres the attribute a failure. Most attributes that have a zero threshold are not critical. When they decrease, it just means that you drive gets older. Other attributes have thresholds greater than 0 and are often critical.

The three columns together tell you the status of an attribute.

"current" means the current value. Usually it is at 100 when everything is ok. Higher values often mean that the attribute has never been updated (implies 100).

The column "worst" tells you what worst value SMART has ever assigned to this attribute.

"threshold" is the absolute health threshold and indicates the value at/below which SMART consideres the attribute a failure. Most attributes that have a zero threshold are not critical. When they decrease, it just means that you drive gets older. Other attributes have thresholds greater than 0 and are often critical.

The uncorrectable sector count is an important attribute that very often indicates a total failure. Watch this attribute very closely. If it increments too rapidly, it is better to look for a replacement drive. SMART is not always implemented honestly, in my opinion. 100% health with 8 uncorrectable sectors is such a case. Try to do a surface scan, but before you do such an operation with high I/O load, make a backup.