conserving CompactFlash writes

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Previously Dan Jacobson <jidanni@jidanni.org> wrote:
> In http://www.toshiba.co.jp/p-media/english/support/cf_faq.htm it says
> CompactFlash's "number of times of writing : 100,000 times."

> So how does one do his writes wisely to conserve the number of writes
> made?

> Does e.g., Unix's
> $ cp *.txt /compactflash
> use only one write? Or it is one write used per disk block, etc.?

Unix is more difficult: Most Unix filesystems keep an "last accessed"
timestamp for each file. So you are writing the disk on each read
to a file!

One solution is to use a RAMDISK and copy files over to flash
e.g. once an hour. If you need to read the flash, mount it
read-only.

One other thing: That is 100.000 write times per individual sector.
The overall number of writes does not matter. It is just the
number of writes in each specific place.

Arno
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Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

On 2004-11-14, Arno Wagner <me@privacy.net> wrote:
> Previously Dan Jacobson <jidanni@jidanni.org> wrote:
>> In http://www.toshiba.co.jp/p-media/english/support/cf_faq.htm it says
>> CompactFlash's "number of times of writing : 100,000 times."
>
>> So how does one do his writes wisely to conserve the number of writes
>> made?
>
>> Does e.g., Unix's
>> $ cp *.txt /compactflash
>> use only one write? Or it is one write used per disk block, etc.?
>
> Unix is more difficult: Most Unix filesystems keep an "last accessed"
> timestamp for each file. So you are writing the disk on each read
> to a file!

It could be mounted with the "noatime" option to stop that behavior.
 
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Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

Previously Ben Scott <benscott@nwlink.com> wrote:
> On 2004-11-14, Arno Wagner <me@privacy.net> wrote:
>> Previously Dan Jacobson <jidanni@jidanni.org> wrote:
>>> In http://www.toshiba.co.jp/p-media/english/support/cf_faq.htm it says
>>> CompactFlash's "number of times of writing : 100,000 times."
>>
>>> So how does one do his writes wisely to conserve the number of writes
>>> made?
>>
>>> Does e.g., Unix's
>>> $ cp *.txt /compactflash
>>> use only one write? Or it is one write used per disk block, etc.?
>>
>> Unix is more difficult: Most Unix filesystems keep an "last accessed"
>> timestamp for each file. So you are writing the disk on each read
>> to a file!

> It could be mounted with the "noatime" option to stop that behavior.

Yes, that is one thing. Another is to turn of logging to
disk completely. Otherwise you will have some inodes modified
all the time.

There are Linux distros aimed at being run from flash. These
should already include most of the things that can be done.

Arno

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For email address: lastname AT tik DOT ee DOT ethz DOT ch
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"The more corrupt the state, the more numerous the laws" - Tacitus