(ever seen a DatA General hard disk crash? and fill the room with vast amounts of aluminum wool, curly cues? lots of fun back then. (im backed up ) (no lack of cooling ever.) heat is the #1 killer and power surges, I run a UPS. I'm typing this, on an old PC, running one of the first 1gb HDD ever made. If you run the disk cool, it will last a long time and you many never run out of spare cylinders. and are read again, and usually pass the test for CRC errors. Point 2: all HDD have natural read errors, you can learn that at Seagate too, if you want. So like he says above, it's not important unless you have many drives of the same kind and you see some odd trends. Whether the manufacturer chooses to report raw errors whenever there are 3 bad reads or after the calibrate is up to them. This is deep in the firmware, but happens continually in the background, all transparent to the user. If the drive is still not ok it will map that sector to one of the spare sectors. There is a 3 times rule in the drive's firmware - it reads a sector 3 times and if all 3 times it is bad then it may do a "recalibrate" on the fly, and read 3 more times. This is all transparent to the outside world - except for the SMART util.Įach manufacturer can do as they please, so some set the error counts to zero, even though there might be 10 bad sectors as soon as the drive is manufactured. In fact they are "logically swapped out" - the bad sector is mapped to a new, good, spare cylinder sector (it has spare cylinders - think of cylinders as tracks). So they map them out, this means the drive skips bad sectors. In the olden days, we had to enter the bad sectors in to the HDD controllerįrom a list on paper that came in the new drive box, so the controller skips them. There is no perfect HDD, never was, never will be, (history and fact). Unsuccessful attempts are counted as well as successful. The raw value of this attribute shows the total number of attempts to transfer data from reallocated sectors to a spare area. You will see how HDD's are made, tested and how they really work. Reallocated Event Count - Count of remap operations (transfering data from a bad sector to a special reserved disk area - spare area). If you read the data sheets (white papers) say at
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