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List:       zaurus-general
Subject:    Re: [Zaurus-general] general questions about flash memory
From:       Jerome Campbell <jerbell () tku ! us>
Date:       2003-01-26 23:10:20
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The limit is the same for all modern flash chips (that you and I can
afford anyway), hence its the same for devices built using them.

The chip specification is for 100,000 erases. In practice you get more
then 100,000 writes if your not writing the full capacity of the card each
time you write new data. The flash only has to erase a block after it has
no more empty blocks left to store the new data.  There are usually at
least 16 blocks in a flash device and they move data around to avoid "hot
spots".  If your writing data that is flash's block size and your
replacing data uniformly across the flash you could theoretically get 1.6
million writes.  Remember tho that a file written to dosfs is a minimum of
four flash writes plus many more if the file is fragmented.

The sharp ROM writes the entire flash at once and leaves it read only, I
doubt anyone will ever wear it out that way.  The OZ ROM lets you write to
the internal flash which could wear it out very fast if some program goes
nuts and writes to the flash over and over again.  The next Z uses an OZ
like flash configuration so I guess the chances of a runaway program or
mis-configuration destroying the Z while its under warranty are
acceptable.  I haven't heard of it happening with OZ...yet...




On Sat, 25 Jan 2003, James Oldham wrote:

> I'm vaguely aware that flash memory can take a limited number of writes.
> 
> Is the "limit" the same for all media formats?
> 
> Is the limit fixed or variable?
> 
> Is the limit per sector or for the whole device?
> 
> Does that include the flash ROM in the Zaurus?
> 
> If I switch to the Crow ROM or OZ (I've tried both and like them, but always go \
> back to the standard ROM), can I expect the internal flash to fail at some point? 
> If so, is there any way to guard against that?
> 
> 
> 
> 
> 
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