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SANtools® S.M.A.R.T. Disk Monitor (SMARTMon-UX)32

1.10 Defect Reporting

When you invoke the -Y command, it instructs the software to report all primary (factory) and grown defects.\

The primary defect list (PLIST) is the list of defects that may be supplied by the original manufacturer of the device or

medium. They are considered permanent defects. The PLIST is located inside a reserved area and is not accessible

except through a low-level SCSI command, READ DEFECT DATA. Once the original PLIST is created at the factory,

it is not subject to change.

The grown defect list (GLIST) includes all defects sent by the application client or detected by the device server. The

GLIST does not include the PLIST. The GLIST shall include:

· Defects detected by the format operation during medium certification

· Defects previously identified with a REASSIGN BLOCKS command

· Defects previously detected by the device server and automatically reallocated

The grown defect list can be cleared by performing a special FORMAT UNIT command and providing it specific

parameters to clear the list. We do not provide that capability because we can not see any real-world situation where

one would want to clear the grown defect list. If we were to allow you to clear the defect list, eventually your operating

system will attempt to put good data on blocks that were previously marked as bad and you would have data loss.

Below is sample output using the -Y command. Note that the device has no grown defects. This disk is reasonably

new.

[root@rh90 smartmon]# ./smartmon-ux -Y /dev/sg0

Discovered SEAGATE ST373307LC S/N "3HZ0381E" on /dev/sg0 (Not Enabling SMART)(70007 MB)

Total grown defects: 0

Total Primary (factory) defects: 1749

Head Cylinder Sector

---- -------- ----------

2 49 885

2 84 64

2 85 172

2 86 279

2 86 280

... (trimmed response here)

1 48047 31

1 48048 475

Terminating program.

It is worth noting that not all disks support the low-level command to report either factory and or grown defects. If that

is the case, smartmon-ux will continue without reporting such defects.

You should also know that disks can save defects in one of several formats. The defect list format is set at the time

you (or the factory) issue the FORMAT UNIT command and clear the defect list. Smartmon-ux supports all

ANSI-defined defect formats and will report them in the default format set at the time the device was initially

formatted.

Note for LINUX users:

If you are not using the /dev/sg type drivers, you will probably not see a defect dump. As discussed earlier in this

document, the standard /dev/sd class drivers are limited to 4KB commands. This is not sufficient to return a defect

map, since it takes 8 bytes to report a defect. Adding overhead gives you room to report only 500 defects. This would

seem like a lot, but it is not. Larger disks can have thousands of factory defects.

The output below is for the same disk, but the command did not use the sg class drive

[root@rh90 smartmon]# ./smartmon-ux -Y /dev/sda

Discovered SEAGATE ST373307LC S/N "3HZ0381E" on /dev/sda (Not Enabling SMART)(70007 MB)

Total grown defects: 0