Solid State Hard Drive Spec's

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MrAl
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Solid State Hard Drive Spec's

Post by MrAl » Tue May 26, 2009 2:44 am

Hello there,

I read the ads for the SSD's for computers and the manufacturer rants and raves about how great they
are and that they have a MTBF of 1.5 million hours.

Well, 1.5 million hours is the same as 171 years, but yet the manu only guarantees them for 2 years.
What gives? Either they work for a very long time or they only work for 2 years...which is it?
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Robert Reed
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Re: Solid State Hard Drive Spec's

Post by Robert Reed » Tue May 26, 2009 6:44 am

I have seem some MMIC devices with MTBFs in "light years" and come with no guarantee period whatsoever. I don't know how they arrive at these figures so I guess its just a consumer confidence thing. Certainly none of us will be around to ever prove this!

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Janitor Tzap
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Re: Solid State Hard Drive Spec's

Post by Janitor Tzap » Tue May 26, 2009 7:17 am

Well.....
The MTBF of the drive may be rated for 1.5 million hours.
But there is all the supporting electronics.
Like; Voltage regulators, Data Line Buffers, Processors,
and components such Electrolytic Capacitors that only have a live expectancy of 10,000 hours or so.

True, the SSD's have been around awhile now.
But until the other components can be upgraded, or improved.
The manufacturers are going to be cautious about the warranties. :wink:

If you look at the warranty on most mechanical hard drives.
It is 2 to 5 years tops.

Here's another point......
Most computer equipment is replaced every 2 to 5 years.
Thus, having a drive that is warrantied for longer than that.
Is consider foolish, if it is going to be replaced in that time period any way.

Just my two cents on the subject.


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Re: Solid State Hard Drive Spec's

Post by SETEC_Astronomy » Tue May 26, 2009 8:56 am

My guess is maybe it has something to do with wear leveling and the limited number of writes. The storage memory can be used to a point where it no longer works as intended, nothing has failed, it's just been used up (worn down?). By providing a limited warranty they limit liability for people returning drives after they've written to them to the point it ceases to store data. Using a SSD as a memory paging file or SWAP space will kill it in short order or so I've read. No personal experience on the matter, still a bit to pricey and a few previously unmentioned SSD caveats have come to light recently.

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Bob Scott
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Re: Solid State Hard Drive Spec's

Post by Bob Scott » Wed May 27, 2009 6:29 am

Are you guys talking about those USB thumb drives like the Data Traveler?
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Re: Solid State Hard Drive Spec's

Post by SETEC_Astronomy » Wed May 27, 2009 6:54 am

It's the same storage technology but SSDs (Solid State Discs) are solid state hard drives that connect using SATA (Haven't looked to see if a PATA version is out there). The pros being, higher reliability with no moving parts, no platters to get damaged, no head crashes, not vulnerable to stray high powered magnets, lower power consumption and a few others. Some would argue a few of those points but I'm just giving you the typical SSD sales keywords.

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Re: Solid State Hard Drive Spec's

Post by haklesup » Wed May 27, 2009 2:40 pm

The drawbacks are typically higher cost, lower data transfer rate and smaller maximum available capacity but those bottlenecks may be diminishing (if they were gone, we would see more activity in the sales of these).

Do you have a link to one you are looking at?

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Re: Solid State Hard Drive Spec's

Post by stevech » Wed May 27, 2009 7:38 pm

haklesup wrote:The drawbacks are typically higher cost, lower data transfer rate and smaller maximum available capacity but those bottlenecks may be diminishing (if they were gone, we would see more activity in the sales of these).
What I've read is that even with clever wear-leveling algorithms (which aren't mature yet), the limited number of write cycles in flash chips means the SSDs will fail much sooner than magnetic disks.

No thanks, I say.

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MrAl
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Re: Solid State Hard Drive Spec's

Post by MrAl » Wed May 27, 2009 9:14 pm

Hi,

One of my concerns is that when one is used for an operating system drive, that drive is going
to be written to quite often and i dont see any wear leveling routine being able to handle
this chore very well, especially the paging file but not limited to that alone.

Here is a link to several drives:
http://www.circuitcity.com/applications ... te%20drive

They range in price depending on the capacity.
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philba
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Re: Solid State Hard Drive Spec's

Post by philba » Thu May 28, 2009 7:37 am

I'm pretty sure the SSDs that are HDD replacements (i.e. SATA devices) have decent wear leveling. In general, I don't see much benefit - HDDs are pretty fast and surprisingly reliable. There are special cases where they make sense but definitely the mainstream. On top of that, HDD technology keeps getting better.

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MrAl
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Re: Solid State Hard Drive Spec's

Post by MrAl » Thu May 28, 2009 8:24 am

Hi philba,

Yeah, that's true, and i saw a 2 Terabyte drive the other day at one of the stores too.
That's a heck of a lot of storage space. Petty amazing really.

I guess i had this wild idea that the SSD's might be super reliable and last a long
time so if we ever could afford to put them in all of our computers we could get
a nice long run time out of our drives without worrying about a crash. With a
guarantee of only 2 years or so, that's even less than a normal HD. That doesnt
impress me at all.
Also, if the drive defrags it takes it closer to it's last write cycle ha ha.
Thus, i see the ad's now saying:
"Do not defrag this hard drive".
Had to laugh at that one.

With windows constantly writing to the hard drive, i cant see how a drive
like this would last very long. I went through the same thing contemplating
the use of a USB drive for the operating system...doesnt seem plausible just
yet...too bad.
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haklesup
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Re: Solid State Hard Drive Spec's

Post by haklesup » Thu May 28, 2009 8:31 am

I don't really see a benefit for desktop of fullsize laptop at this point, a 320GB flash would cost a fortune compared to a HDD (8x to 12X more) and HDDs are a very very mature technology with some drives consuming quite low power. However, I am seeing them appear in netbooks and that may be a good use especially if it enables instant boot up. I suppose it might be a good alternative in a ruggedized notebook that might see an occasional fall. (if your dropping your desktop PC, you have another kind of probelm). Give it a few more years and there may be little difference (moores law will help there).

The only HDD i have had fail in the last 10 years lasted 6-7 years in a notebook. Before that, I had some lasting only 2-3 years. They generally last longer than the OS installation on them :(

Last year we trashed some full bay MFM 30MB drives Now those were dinosaur brains

The only things with longer than 2 year warranties are new car power trains. Thats just standard industry practice and dosen't really reflect the real relaibility.

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philba
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Re: Solid State Hard Drive Spec's

Post by philba » Thu May 28, 2009 8:52 am

By the way on the reliability front. I know a number of people that work at Dell in their notebook line. They tell me that the top 3 failures were: hinges, screens and something else. HDD failures were something like #6 and a very small percentage of all failures.

On defrag - you don't need to defrag an SSD. It's not needed.

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MrAl
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Re: Solid State Hard Drive Spec's

Post by MrAl » Sun May 31, 2009 12:11 am

Hi philba,

Oh yes, i thought that it would not be needed to defrag because the reading would be a bit
different, more random without the same delays, but i wouldnt doubt it if a defrag could help.
In any case, i would bet people have done this and possibly some software kicks in automatically
(XP starts Defrag sometimes by itself) so people would have to know about this and disable it.

I thought about this once i got a bigger USB drive too. How would i defrag it if needed?
I came up with the idea that if it is used mainly for longer time storage that no erases would
be needed, but a problem with that seemingly great idea is that Windows doesnt always put
files one immediately after the other on a hard drive. It leaves spaces between files.
This creates fragmentation. The only way i know to deal with it is to copy all the files
to the main 'standard' hard drive in the system, erase, then copy back to the USB drive. This isnt
perfect, but at least then the system only erases once and writes once. If defrag is allowed
to run on a USB drive, it will write and erase and write and erase and do that over and over
again sometimes and that will use up the max write cycles much quicker.

Another drive i have for more temporary storage, i write a bunch of stuff and dont erase
anything until it gets full. Then i erase a bunch of stuff that clears massive amounts of
space, getting it ready for another large set of data. If i were instead to erase a few files,
write a few files, erase a few, write a few, it would get badly fragmented after awhile.

More ideas welcome.
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