Intel X25-M SSD: Intel Delivers One of the World's Fastest Drivesby Anand Lal Shimpi on September 8, 2008 4:00 PM EST
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What Happens When Your SSD Fails?
When your hard drive dies we all know what happens. You go to turn on your machine one day and your OS doesn't boot, or your drive stops getting detected. But with SSDs their lifespan is far more predictable, so what does happen as they near the end of their life? A well designed SSD will have a good enough wear leveling algorithm to make sure that all blocks in the device get equal usage, so that when they fail, they do so at the same time.
Intel's SSDs are designed so that when they fail, they attempt to fail on the next erase - so you don't lose data. If the drive can't fail on the next erase, it'll fail on the next program - again, so you don't lose existing data. You'll try and save a file and you'll get an error from the OS saying that the write couldn't be completed.
The beauty here is that the SSD knows exactly when it can't erase/program a block, and if the drive knows, then you can use software to ask the drive what it knows. In the near future Intel will be releasing its own SSD tool that will let you query two SMART attributes on the drive: one telling you how close you are to the rated cycling limit, and one telling you when you've run out of reallocating blocks. The latter is the most important because Intel fully expects these drives to outlast their rated limits. As bad blocks develop, the SSD will mark them as such and write to new ones - by telling you when it has run out of bad blocks (or nearly run out of bad blocks), you'll know exactly when you need a new hard drive.
This is hugely important. While Intel's SSDs aren't exactly cheap, the beauty of flash is that it follows the same Moore's Law that CPUs do. In the next ~18 months you'll be able to get a 160GB drive for the price of the 80GB, in another couple of years we'll be at 320GB for the same price (most likely lower as SSD demands increase). Within the next five years we'll be in a situation where the fans in your system are more likely to fail than your hard drive, and if your drive does happen to fail it'll tell you well in advance. How nice of it.