How smart is S.M.A.R.T.?

[parabellum7 at yahoo.com]

Greetings!


I have a 500GB Seagate ST3500312CS SATA drive salvaged from a decommissioned DVR. The DVR's OS said SMART status OK. The latest Seatools disk utility from the Seagate website says the drive is A-OK (short test, long test, full erase, re-test) no errors found. 

However, the Gnome disk utility in Mint 17 says 'Threshold not exceeded' and 'Disk is OK, 178 bad sectors'. 

Some other SMART attributes displayed:

ID1		Read Error Rate: 152141757
ID5  	Reallocated Sector Count: 178 sectors
ID187 	Reported Uncorrectable Errors: 0 sectors
ID198	Uncorrectable Sector Count: 0 sectors
ID199	UDMA CRC Error Rate: 0


GSmart Control 0.8.7 is reading the same thing, 178 sectors, but also says it's OK. 

running an e2fsck from gparted reports 0 bad blocks. 

I've also retested in another machine with different cables to minimize the possibility of bogus hardware or BIOS issues, but the results remain the same. 

Seagate's website has a FAQ that says their tools should be the final say as they're designed to work correctly with their drives. 

Normally a bad sector or two wouldn't bother me, I have drives that have been running for years like that. I just keep backups fresh and check for bad sector growth. A few bad sectors is within spec and that's why HDD's have a reserved area. Yet somehow 178 sectors seems like a lot. 

Should I trust this drive for anything more than a paperweight? 

Should I trust anything with the words 'smart', 'affordable', or 'free' in the name?  ;]


Thanks!


--Kenn