Add SSD SMART attribute support.

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A few details about SSD attributes can be found here: 
http://www.xtremesystems.org/forums/showthread.php?t=238421

Quote: "Indilinx SSD’s

ID Hex Attribute
----------------------
01 (01) Read error rate
09 (09) Power on Hours
0C (12) Device power cycle count
C7 (199) Write Sectors Total Count
CD (205) Max PE Count Spec
CE (206) Min Erase Count
CF (207) Max Erase Count
D0 (208) Erase count average
D1 (209) Remaining drive life in % by Erase count

There is a really useful post that explains the above 
http://www.ocztechnologyforum.com/forum/showpost.php?p=451016&postcount=1 .
To find out total writes: ID# 199 x 512
To find out the % of write cycles used: ID# 208 x 100/ID# 205 = % of write 
cycles used.
To estimate remaining hours of use: ID# 9 (100/7.26) – 1 (x ID# 9)
To convert the above to years: / 8760

Intel SSD’s

ID Hex Attribute
----------------------
05 Re-allocated sector count
09 (09) Power on Hours
0C (12) Device power cycle count
CO Unsafe shutdown count
E1 (225) Host writes
E8 (232) Available Reserved Space
E9 (233) Media wear out indictor
B8 End to end error detection count

Info on Intel S.M.A.R.T attributes can be found here 
http://download.intel.com/support/ssdc/hpssd/sb/intel_ssd_toolbox_user_guide.pdf
 . For G2's (with the latest f/w) S.M.A.R.T data can be obtained from the Intel 
Drive Toolbox.

As far as I know all ID’s are the same between a G1 and a G2 apart from B8, 
which is G2 only.

Key ID’s

E1 – HostWrites
This attribute reports the total number of sectors written by the host system. 
The raw value is increased by 1 for every 65,536 sectors written by the host.

E8 - Available Reserved Space
This attribute reports the number of reserve blocks remaining. The attribute 
value begins at 100 (64h), which indicates that the reserved space is 100 
percent available. The threshold value for this attribute is 10 percent 
availability, which indicates that the drive is close to its end of life. Use 
the Normalized value for this attribute.

E9 Media Wearout Indicator
This attribute reports the number of cycles the NAND media has experienced.
The normalized value declines linearly from 100 to 1 as the average erase cycle 
count increases from 0 to the maximum rated cycles.
Once the normalized value reaches 1, the number will not decrease, although it 
is likely that significant additional wear can be put on the device. Use the 
Normalized value for this attribute."

Original issue reported on code.google.com by moel.mich on 25 Jul 2010 at 12:06

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Original comment by moel.mich on 30 Jul 2010 at 10:35

• Added labels: Type-Enhancement
• Removed labels: Type-Defect

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Initial support added in r252 - available for download at 
http://ohm.werelds.net/open-hardware-monitor-0.2.1.0-r252.rar

Original comment by paulwere...@gmail.com on 8 Oct 2010 at 12:22

• Changed state: Started

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Original comment by moel.mich on 28 May 2012 at 3:19

• Changed state: Fixed