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talljasperman's avatar

Why do Solid State Drives crash more than the old fashioned Hard Drives?

Asked by talljasperman (21739points) February 20th, 2013

I would like to know more than what wikipedia states.

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8 Answers

Crumpet's avatar

I didn’t think they did… I’ve got a solid state hard drive in my macbook air that I’ve had since 2010, and it’s never crashed once.

blueiiznh's avatar

Some education.
Traditional disk drives have read write heads that fly over an oxide coated platter on a thin cushion of air. If the head contacts the spinning platter it is termed to crash. In epic crashes it creates a very distinct odor and a buzz saw sound. It renders data loss in the spots that it crashes even in lab forensics.
An SSD has no moving parts and thus cannot “crash” in the physical sense. It however can become inoperable.

dabbler's avatar

Solid state drives don’t crash at all in the same way that spinning disk drives do.
A spinning drive can literally have one of its read/write heads crash into the ferrous surface, often destroying both. These drives have been around a long time, however, and a lot of safeguards are built into them to help avoid it. If the power goes out, or the drive senses free-fall it will park the heads in a safe place so no crashing.

However the semiconductor memory in a solid state drive can have its state changed only so many times and then it starts becoming unreliable. That number tends to be in the several thousands.
Early solid-state drives had trouble especially in places that were written/re-written frequently such as directory areas or a portion used as swap space.

Current SSDs have several features built-in to help avoid failures.
The semiconductor structures are fortified for longer write-cycle lifetime, more state change cycles.
There are several zones of spare memory that can be used when an active region wears out, commonly as much as 20% extra.
The SSD controllers also keep track of how many times each area has been used to load-level where the next write goes, and they can move data from an area that has been used a lot into a less-used area.

jerv's avatar

I was confused by your assertion, so I had to check the Wikipedia page to see where that bit of misinformation came from. After all, sometimes Wikipedia is wrong.

Nowhere on the Wikipedia page did I see where it claims that SSDs crash more; the closest I saw were a few statements that they are more reliable, and when they do fail, they do so more completely and with less warning than a traditional hard drive.

El_Cadejo's avatar

I would assume theyre more reliable since they dont have the platter of disks and the needle likd HDDs. Its those disks malfunctioning in some way thay usually causes HD failure.

dabbler's avatar

@uberbatman The lack of spinning disks certainly eliminates any issues related to them, including bearings, motors, surface faults, head faults… and crashes.

However the nature of static RAM gives them limited capacity to switch values. The can change their values only so many times, several thousand times but still after that they get unreliable.

They get better all the time, and except for a couple rotten brands (OCZ!) most of them are pretty good these days. (Intel, Samsung, Crucial and Kingston seem to lead the reliability charts. No coincidence these same companies make some of the more solid DRAM, too).

jerv's avatar

@dabbler Several thousand? You are missing a few zeros there.

Read what this article has to say about that and you’ll see that they’ve come a long way.

dabbler's avatar

@jerv True, several thousand is on the low end of the reliable figures I’ve seen.
And it’s true the better ones are ten times that, and enterprise/data center drives are another order of magnitude even better but cost quite a bit more too.

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