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Re: JFFS compression and hard links.



David Woodhouse[SMTP:dwmw2@xxxxxxx.org] wrote:
> On Tue, 9 Jan 2001, Tim Riker wrote:
> 
> > I actually would like a user space compress tool and not to have
> > "compress on the fly" support.
> 
> Omitting runtime compression will be compile-time option.
> 
> > This simplifies the model greatly and speeds up the normal write
> > performance.
> 
> Flash writes are _slow_. Compression is relatively fast. I'd be
> surprised if compressed writes didn't turn out to be generally faster
> than uncompressed writes.
> 
That may be true for *many* systems. Actually, the flash write speed
depends on the kind of flash chip that you are using, and compression
is highly CPU dependent. The (16-bit) word programming time is <10us
for many flash chips. I doubt that you can do compression that fast on
the Dragonball with 16 MHz, for example.

-Erwin


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