[sane-devel] Need sane docs

m. allan noah kitno455 at gmail.com
Thu May 5 18:18:59 UTC 2016

Xsane has no networking code in it. Everything you have described so
far sounds like a problem in the brother4 backend. I suggest you try
the same test using scanimage at the command line, and if it is still
slow, compare to the windows driver. If you see a difference, ask
Brother about brother4.


On Thu, May 5, 2016 at 2:05 PM, Gene Heskett <gheskett at shentel.net> wrote:
> On Thursday 05 May 2016 10:31:53 Richard Ryniker wrote:
>> I doubt a gigabit Ethernet connection will make any significant
>> difference.
> After investigating the lcd panels network settings for a wired lan, and
> finding the best it can do is 100mbit-fd, that switch isn't going to do
> a lot of good.  But the old one had a port that comes and goes very
> intermittently, so I expect its been tapped by a local lightnings EMP
> somewhere along the 6+ years its been in use here.
> I as I said before, can ping it in an average time of .3 milliseconds.
> But when xsane inits on the lan address, on launch from a shell, the
> little "looking for scanners" box is drawn for about 1 screen refresh
> and its wiped.  Then the is a 5 or 6 second pause before xsane draws its
> windows.  Hooked up with a usb cable, the opening screen draws are a
> small fraction of a second being drawn.  And this is perceptually the
> exact same lag as the command delay is. So while its working, I'm of the
> opinion that the command lag is in xsane someplace.
> Since 99.9% of the scanners sane runs are hooked up to a USB cable, this
> lag may be a bug someplace that because its so rare, has not been well
> investigated.  The wheel only squeaks on the 29th day of February sort
> of thing. ;-)
> According to an xsane -v:
> gene at coyote:/etc$ xsane -v
> xsane-0.998 (c) 1998-2010 Oliver Rauch
>   E-mail: Oliver.Rauch at xsane.org
>   package xsane-0.996
>   compiled with GTK-2.24.10
>   with color management function
>   with GIMP support, compiled with GIMP-2.6.12
>   XSane output formats: jpeg, pdf(compr.), png, pnm, ps(compr.), tiff,
> txt
> From that it looks like its been a while since xsane has had any great
> amount of TLC.  Its also odd that the "about screen" says 0.998, not
> 0.996. ???
> Perhaps its time to troll thru the networking code & see if anything
> bites? So I'll renew my offer to serve as a test mule again.
> But please don't cut too deep, I am on 7.5 mg of warfarin a day for blood
> thinner. :)  One of those defective takata air bags could kill me long
> before the sirens could be heard in the distance. :(
>> Data rate from your scanner is dependent on the
>> mechanical speed of the sensor and scan resolution.  If you scan a
>> page 8.5 by 11 inches at 600 pixels per inch resolution with 24 bits
>> per pixel, there is about 100 megabytes of data.  With a 100-megabit
>> Ethernet connection, that is about 10 seconds transmission time.  If
>> your scanner requires 10 seconds for mechanical movement at that
>> resolution, the Ethernet connection should not limit scan speed.
>> At 1200 pixel per inch resolution, there would be four times as much
>> data (400 Mbytes.) This would need roughly 40 seconds to transfer
>> using a 100-megabit Ethernet connection, but your scanner likely moves
>> more slowly at that resolution.  If you can scan faster than 40
>> seconds with a USB connection at that resolution, then gigabit
>> Ethernet might help.  Do you have any reason to believe your machine
>> even supports gigabit Ethernet?  Most do not.
>> Eight seconds instead of two seconds to start a scan sounds like some
>> sort of time-out situation.  The tcpdump command could provide some
>> details about timing of the Ethernet traffic, though interpretation of
>> the data might be a challenge.
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page <http://geneslinuxbox.net:6309/gene>
> --
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