[Asterisk-Users] Asterisk 1.0.2, Zaptel 1.0.2, Linux 2.6.9 on a PCEngines WRAP\Soekris net4801 in Compact Flash

[Steven Critchfield]

On Tue, 2004-11-02 at 22:39 +0100, Goran Obradovic wrote:
> I had huge production problems with CF cards just a month ago. I used to
> live in Canada and still have some business there - electronic voting
> equipment. So, we have optical voting devices with 256, 512, and 1GB CF
> cards for election definitions and voting records. Last month on Alberta
> elections we had 5 Kingston 256MB cards failing during the elections. That
> was a nightmare. It is interesting that 512 and 1GB cards were ok even with
> more writes. In any case, if you do something like this first test some
> cards for long period of time. Make some script that will constantly write
> and read the card and see when they fail. 
> Goran

Reads are non destructive, writes produce wear and eventually blocks
start to fail. the 256meg modules you mention above where probably older
and used a different technology. 

Not to mention all flash memory runs in a round robin writing fashion,
so each block should hopefully get equal usage. The smaller cards just
happen to make the round trip faster than the larger cards.

Use of a decent OS and filesystem should help detect and avoid bad
blocks, but you eventually will end with failure just like any other
media.
-- 
Steven Critchfield <critch at basesys.com>