oryoki2000 wrote:
> Walter Knapp wrote:
>
>
>>...you can reuse a MD disk a million times.
>>Will compact flash stand up to a million connects
>>and disconnets? How many years will the
>>internal battery last? And so on.
>
>
> Walter has often raised reasonable questions about the
> suitability of Compactflash memory for field recording.
> This issue of durability, however, is *not* one of them.
>
> "A million disconnects" would take 24 disconnects every
> day for 114 years. The Compactflash Association standards
> include a more reasonable specification of 1 million
> re-writes, and 10,000 insertions at a minimum.
>
> Top vendors like Lexar and Sandisk offer a lifetime
> warranty on their Compactflash products. Compactflash
> is used in flight data recorders because they often can
> survive a plane crash.
>
> And I hope we can put this issue of "battery life"
> to rest. Compactflash does not use a battery of any
> sort to maintain the data in the card. Once it's written,
> the data will last a minimum of 10 years without any
> connection to a powered device.=20
>
> So criticize Compactflash for being too expensive,
> or for requiring a download to computer for archiving.
> But don't be concerned about its durability.
I'll tell that to the ones I tried in my digital camera that could not
hold the image file for more than a few weeks. When I asked someone in
the industry I knew familiar with what's in them I was told that there
is a small current circulating in the memory to maintain it. And that,
although the loss was small, a energy source was necessary to maintain
it. I went back to Type III hard disks for my camera. I was glad I'd
only borrowed the ones I tested.
But what do I know, I'm just a retired Biologist, maybe they maintain
that current using the force now. Certainly the ones I used were not the
current generation cards.
Walt
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