[Baypiggies] File IO question

[Ken Seehart]

Ouch.  I had not considered that.  I didn't know FLASH was so fragile.

Mike Cheponis wrote:
> Bryan is right.
>
> I suggest you glue on a piece of battery-backed (or super-cap-backed) SRAM for your semaphore, or maybe use FRAM:
> http://www.fujitsu.com/emea/services/microelectronics/fram/
> http://www.ramtron.com/
>
> You definitely don't want to beat on the flash FS too much...
>
> -Mike
>
>
> On Tue, 25 Jul 2006, Bryan O'Sullivan wrote:
>
>   
>> Date: Tue, 25 Jul 2006 10:53:21 -0700
>> From: Bryan O'Sullivan <bos at serpentine.com>
>> To: davidoff56 at alluvialsw.com
>> Cc: baypiggies at python.org
>> Subject: Re: [Baypiggies] File IO question
>>
>> On Tue, 2006-07-25 at 10:32 -0700, Monte Davidoff wrote:
>>
>>     
>>> 1. Write new data file.
>>> 2. Invoke /bin/sync to ensure the new data file is written to disk, if
>>> shelve did not take care of this already.
>>>       
>> Just use os.fsync(fp.fileno()).
>>
>>     
>>> I'm also working on an embedded Linux application that writes to a flash
>>> drive.  To get journaling, I've used XFS on the flash drive, although I
>>> have not tried JFFS2.
>>>       
>> This is not a very good idea.  Linux's flash filesystems are designed
>> specifically to limit the number of write cycles they make to any given
>> region of memory ("wear leveling"), which disk-oriented filesystems do
>> not need to worry about.  You'll significantly reduce the usable
>> lifetimes of your flash devices if you use an inappropriate filesystem.
>> Also, XFS is enormous, hardly a good fit for a presumably
>> resource-constrained embedded system.
>>
>> 	<b
>>     
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>   

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