A couple of questions

A couple of questions

[Adil EL YOUSSEFI]

Hi everybody,

 I have some questions reguarding JFFS2 :

-> Under what license it is released. My boss wants to
 know if he would have to pay in order to put JFFS2 in
our product.

-> We are using a flash device with different sector
sizes ( 1*32k, 2*16k,1*64k and the others are 128k ),
What size should the JFFS2 reserved sectors have then
?

-> If JFFS2 is used without enabling compression, will
there still be corner cases in GC requiring 5 reserved
sectors and not 2. 

-> Why can't JFFS2 be used on Compact flashes ? 

Thanks,




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Re: A couple of questions

[David Woodhouse]

adilos2@yahoo.com said:
>  -> Under what license it is released. My boss wants to
>  know if he would have to pay in order to put JFFS2 in our product.

Under what licence is your product? JFFS2 is under a dual licence - both 
GPL for compatibility with the Linux kernel, and RHEPL for use in eCos. 

>  -> We are using a flash device with different sector sizes ( 1*32k,
> 2*16k,1*64k and the others are 128k ), What size should the JFFS2
> reserved sectors have then ? 

128KiB - the 'major' erase size.

>  -> If JFFS2 is used without enabling compression, will there still be
> corner cases in GC requiring 5 reserved sectors and not 2. 

Probably not. To be honest, it probably wouldn't happen even _with_ 
compression - I just don't like releasing software that'll 'probably' work 
:)

>  -> Why can't JFFS2 be used on Compact flashes ? 

Technically, it can - we now have a 'blkmtd' driver which uses any block 
device as backing store for an MTD device - so it can use any hard drive. 
At the moment, it's painfully slow. Checkpointing ought to fix that, but 
nobody's currently working on implementing that.

--
dwmw2

JFFS2 performance

[Joakim Tjernlund]

Hi all

I am wondering how JFFS2 performance(primarly read performance) is affected by compression.
There are basically 3 types of (de)compression NONE, ZLIB and RTIME. Does it matter which
one is used w.r.t read performace?

 Joakim Tjernlund

Re: JFFS2 performance

[dennis noermann]

On Wed, 10 Oct 2001, Joakim Tjernlund wrote:

> Hi all
>
> I am wondering how JFFS2 performance(primarly read performance) is affected by compression.
> There are basically 3 types of (de)compression NONE, ZLIB and RTIME. Does it matter which
> one is used w.r.t read performace?

i am using ZLIB , and it is slow :(
on a mpc823 with 66Mhz with 2 Intel 28F320 interlaced (32 Bit) with
kernel 2.4.2 it takes 70 seconds to mount a 8Mb uge jffs2 Partition :(

an the read a write actions are slow :( ...

but a 640k partition is mountet realy fast :)

dennis