ZyXEL Communications NSA-2401 User Manual

 Chapter 6 Storage Screens

NSA-2401 User’s Guide

12

Device Power 
Cycle Count

This is the number of times the hard drive has gone through a full 
power on and power off.

13

Soft Read Error 
Rate

Low

This is the number of uncorrected read errors the hard drive has 
reported. If this is not zero, back up your data.

190

Airflow 
Temperature

Low

This indicates the temperature of the airflow measured by a 
Western Digital hard drive. 

190

Temperature 
Difference from 
100 

High

This indicates the value of 100 - the temperature in degrees 
Celsius. Manufacturers can set a minimum threshold that 
corresponds to a maximum temperature.

191

G-sense error 
rate

Low

This is the number of mistakes caused by impact loads.

192

Power-off 
Retract Count 

Low

This is how many times the heads are loaded off the media. 

193

Load/Unload 
Cycle 

Low

This is the number of load and unload cycles into head landing 
zone position.

194

 Temperature 

Low

This is the hard drive’s internal temperature.

195

Hardware ECC 
Recovered 

High

This is the time between ECC (Error Correction Code)-corrected 
errors.

196

Reallocation 
Event Count 

Low

This is the total number of reallocation (remap) operations. The 
raw value is the total attempts to move data from reallocated 
sectors to a spare area. Successful and unsuccessful attempts 
are both included.

197

Current Pending 
Sector Count 

Low

This is the number of unstable sectors awaiting reallocation. If the 
sector is later successfully written or read, this value decreases 
and reallocation is not performed. Only failed write attempts 
cause a reallocation, not read errors. This can be difficult to test 
since only direct I/O writes to the disk cause reallocations, not 
cached writes.

198

Uncorrectable 
Sector Count 

Low

This is the number of errors reading or writing a sector that were 
not correctable. An increase in this value is an indicator of disk 
surface defects or mechanical subsystem problems.

199

UltraDMA CRC 
Error Count 

Low

This is the number of data transfer errors through the interface 
cable according to the ICRC (Interface Cyclic Redundancy 
Check).

200

Write Error Rate / 
Multi-Zone Error 
Rate 

Low

This is the total number of errors in writing sectors.

201

Soft Read Error 
Rate 

Low

This is the number of read/write head off-track errors. If the value 
is not zero, make a backup.

202

Data Address 
Mark Errors 

Low

This is the number of data address mark errors. This could also 
be a different, manufacturer-specific attribute.

203

Run Out Cancel 

Low

This is the number of ECC (Error Correction Code) errors.

204

Soft ECC 
Correction 

Low

This is the number of errors corrected by software ECC (Error 
Correction Code).

205

Thermal Asperity 
Rate (TAR) 

Low

This is the number of thermal asperity errors. Thermal asperity is 
a read signal spike caused by sensor temperature rise due to 
touching the disk surface or contaminant particles.

206

Flying Height

This is the height of the hard drive’s read/write heads above the 
disk surface.

Table 42   S.M.A.R.T. Attributes  (continued)