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Imagine you're working on your computer and suddenly the electricity goes out is there a way to recover the data lost in this case?

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4 Answers

up vote 6 down vote accepted

Yes, but you probably don't have the equipment required to extract it. A residual charge will remain on the capacitors within the memory itself, but it's so small that extremely sensitive equipment is required to detect it, much less read it.

Read this page, section 7.

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wow it's interesting so it can be recovered.what kind of equipment do you mean may you please name if possible? –  Nobody Apr 30 '10 at 9:32
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also, if you've switched the computer back on again you've possibly/probably overwritten everything anyway. –  Shevek Apr 30 '10 at 9:34
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Unfortunately I don't know exactly what equipment it would require. You can write the memory chips off though, since you'd have to scrape away the casing to get at the memory cells. –  Ignacio Vazquez-Abrams Apr 30 '10 at 9:37
    
If you freeze the memory before or after cutting the power it will retain its charge for much longer –  Joey Apr 30 '10 at 10:06
    
Also check out blogs.zdnet.com/security/?p=900 –  Blorgbeard Apr 30 '10 at 10:07
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No; RAM only holds information as long as there is power flowing to the memory. If power is interrupted, the information in memory is lost.

As Shevek said, autosave can help, but in this case the information is saved to the hard drive, not to RAM.

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The only solution is to use an Uninterruptible power supply (or battery backed power supply):

An uninterruptible power supply, also uninterruptible power source, UPS or battery/flywheel backup, is an electrical apparatus that provides emergency power to a load when the input power source, typically the utility mains, fails. A UPS differs from an auxiliary or emergency power system or standby generator in that it will provide instantaneous or near-instantaneous protection from input power interruptions by means of one or more attached batteries and associated electronic circuitry for low power users. The on-battery runtime of most uninterruptible power sources is relatively short—5–15 minutes being typical for smaller units—but sufficient to allow time to bring an auxiliary power source on line, or to properly shut down the protected equipment.

A UPS will also protect you from power surges, which is the opposite danger of having too much electricity ...

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thanks it was helpful –  Nobody Apr 30 '10 at 9:42
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If you mean the main memory of your computer then no, it is not recoverable after power failure

Random-access memory

Some applications have some form of autosave feature which may at intervals save a version of open documents etc.

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may you please say what do you exactly mean by application autosave feature? –  Nobody Apr 30 '10 at 9:29
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Microsoft Word for example will save a back-up copy of your documents every 5 minutes (or whatever interval is configured) in a temporary file. If you have a crash then when you relaunch Word it should detect the presence of the temp file and recover changes up till the last autosave. –  Shevek Apr 30 '10 at 9:32
    
I got it now thanks but lgacio vazquez-abrams says ram is recoverable how do you explain that? –  Nobody Apr 30 '10 at 9:35
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it may be technically possible, but the average user is not going to have the equipment or resources to do so –  Shevek Apr 30 '10 at 10:25
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