On Fri, 28 Nov 2003 [EMAIL PROTECTED] wrote:

> Alan Stern wrote:
> > Are you sure that _all_ values don't work?  I would expect that at least 
> > 128 would be okay.  But no, I can't explain what's going on with your 
> > device.
> 
> I tried some values down until 140, all of them didn't work.
> So i made a jump from 140 to 120 and this value is working now.
> I guess, it's besser to choose even numbers (140, 120) and not e.g. 133. Am
> i wrong?

To be safest, I would choose multiples of 8.  I don't know to what extent 
it matters.

> Yes, that's right.
> And the Linux kernel is much faster (about 40%) in copying data to usb
> storage (at my pc) than win.
> 650MB -> usb storage
> win: 75 sec.
> lin: 45 sec!

Great!

> > It's a little odd that your device can only accept such a small amount of
> > data at a time.  Almost all USB storage devices can handle up to 120 KB
> > (that's why the default value of max_sectors is 240) and most can handle 
> > arbitrarily large amounts.
> 
> How many sectors does kernel 2.4.22 transfer at same time? I couldn't find a
> "max sector" line in it's config file.

No, it was only recently added to 2.6.  I don't know the answer for 2.4, 
but it might not matter.  Other differences make 2.4 slower than 2.6 for 
USB transfers anyway.

> > In the future I expect there will be a way to set the max_sectors value
> > directly, without having to change the kernel source.  In the meantime, 
> > you'll just have to make the change by hand.
> 
> It's important to know for users. I am not the only user with that problem.
> Perhaps a default value of 120 in kernel config would be enough? You could
> change it manually with make config etc.

Maybe.  Yours is the first device I've heard of that worked with 120 but 
not 240.

Alan Stern



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