[Soekris] Industrial grade CF durability

Wim Vandeputte bunbun at kd85.com
Sun Mar 13 17:15:14 UTC 2005


On Sun, Mar 13, 2005 at 01:57:23PM +0000, Stuart Henderson wrote:
> >Stanislav wrote:
> >"Beware of the fact that the flashcards don't have unlimited
> >number of write cycles and that without a special setup
> >most filesystems do some writes even when you don't expect
> >them to (e.g. updating a timestamp a file was last accessed)."
> >
> >I have done an installation on a 1gig card and it booted up perfectly in
> >the computer (not in a soekrisbox) I tried it on. I made a /var/log
> >partition with 300meg space and it seemed to work correctly.
> 
> Modern flashcards are much much better than the older ones, see 
> <http://www.monkey.org/openbsd/archive/misc/0407/msg00539.html>

while it's still good practice to mount certain partitions read-only
(because it's too easy for people to forget to halt a unix machine, pulling
 the power plug from a Soekris is very easy to do) and to put scrap 
partitions like /tmp on mfs, I have no problems in considering CF more
reliable than a harddisk with moving parts.

http://www.sandisk.com/industrial/cf-specs.asp

With garantees up to 2 milion cycles it makes sense to go for industrial
grade CF.

Unfortunatly, Sandisk has announced the end of life of it's line of 
industrial grade products (still a couple of months to order them), so I'm
now looking for an alternative.

Transcend has a line of industrial CompactFlash cards, but it's hard
to compare the marketing lingo with that of Sandisk.

For example, 

http://www.transcendusa.com/products/ModDetail.asp?ModNo=15&SpNo=3&LangNo=0

mentions Durability : >100,000 program/erase cycles

Comparing the Consumer Grade and Industrial grade Transcend, the following 
differences stand out:

0. wider temperature range (0 to 70 versus -40 to 85 degrees Celcius)
1. ECC: 1 bit
2. higher shock resistance

The only thing relevant to 'our' application here is point 1. but I have
no clue how to compare the durability...

Does anybody have experience with alternatives than Sandisk Industrial Grade?

Wim.



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