(05-18-2015, 01:45 PM)Gegenji Wrote: So, I figured I'd put the question out: what causes a HD to go bad?
Incoming wall of text.
I can echo what's already been said here. The Hard Disk (unless you get a Solid State Device) is the only physically moving part in the computer. With any mechanical device, the longer it moves the greater the chance of failure.
If you've never seen the inside of a hard disk drive, here you go:
![[Image: Seagate_ST33232A_hard_disk_inner_view.jpg]](https://upload.wikimedia.org/wikipedia/commons/3/38/Seagate_ST33232A_hard_disk_inner_view.jpg)
Those large metal disks are usually made of ceramic and covered in a magnetically sensitive film. The little armature over top of it is not actually resting on the disk, but hovers at a fraction of a millimeter above it. This particular drive has "three platters". There is an armature between each of the platters as well.
When a drive reads or writes data, that armature swipes in and out across the disk. That is the grinding sound you hear when loading software. The platters themselves are spinning at typically 7800 RPMs.
How do these things typically fail?
1.) Physical Shock (dropping, or vibration) - If enough shock is sustained, the armature may skip or touch the platter. At the speed it is moving, this will actually carve a groove in the disk which will destroy the head making it unreadable.
Another aspect is dust. Drives are typically sealed except for a small port which has a dust filter over it. If anything should get on the platter and collide with the head, again it will scratch the surface and destroy the film.
2.) Faulty Circuitry - On the bottom of each drive is the controller board which interfaces with your computer. Sometimes bad solder connections may cause chips to malfunction and render the drive useless.
3.) Bad Blocks - Sometimes the magnetic film simply fails on the platter. This causes the area to be unreadable and a CHKDSK will flag this as "Bad Blocks" or "Sectors". This is a good indication your drive may die at any moment.
4.) Motor Failure - I have rarely ever seen this become an issue, but the DC motor could fail if the bearings go bad or the coils burn out. Chances of this are extremely low for the life of the drive. If this was to happen it would be as the drives spins up or down since it draws much greater electrical current at that time. You can avoid it from even spinning down by going into your power management software and telling it to keep your drives on 100% of the time.
