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118 wiersze
5.6 KiB
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<!-- received="Sun Sep 7 08:54:15 1997 MST" -->
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<!-- sent="Sun, 07 Sep 1997 17:27:26 +0200" -->
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<!-- name="Rainer krienke" -->
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<!-- email="krienke@mailhost.uni-koblenz.de" -->
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<!-- subject="Success in decreasing backtrackrate on mustec 1200sp in color mode" -->
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<!-- id="199709071153.NAA03617@cave.BitWizard.nl" -->
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<title>sane-devel: Success in decreasing backtrackrate on mustec 1200sp in color mode</title>
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<h1>Success in decreasing backtrackrate on mustec 1200sp in color mode</h1>
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<b>Rainer krienke</b> (<a href="mailto:krienke@mailhost.uni-koblenz.de"><i>krienke@mailhost.uni-koblenz.de</i></a>)<br>
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<i>Sun, 07 Sep 1997 17:27:26 +0200</i>
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<p>
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<li> <b>Messages sorted by:</b> <a href="date.html#145">[ date ]</a><a href="index.html#145">[ thread ]</a><a href="subject.html#145">[ subject ]</a><a href="author.html#145">[ author ]</a>
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<li> <b>Next message:</b> <a href="0146.html">Ignacio Garcia: "Problems with xscanimage (sane 0.63)"</a>
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<li> <b>Previous message:</b> <a href="0144.html">Michael Ritzert: "Re: mustek problems in lineart mode"</a>
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</ul>
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<i>>Rainer Krienke wrote:</i><br>
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<i>><<> =</i><br>
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<p>
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<i>>> | From <a href="mailto:fnevgeny@plasma-gate.weizmann.ac.il">fnevgeny@plasma-gate.weizmann.ac.il</a> Sun Aug 31 23:45:11 >19=</i><br>
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97<br>
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<> | From: Evgeny Stambulchik <<a href="mailto:fnevgeny@plasma-gate.weizmann.ac.il">fnevgeny@plasma-gate.weizmann.ac.il</a>><br>
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<i>>> | Date: Mon, 1 Sep 1997 00:39:30 +0300 (IDT)</i><br>
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<i>>> | To: <a href="mailto:krienke@informatik.uni-koblenz.de">krienke@informatik.uni-koblenz.de</a></i><br>
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<i>>> | Subject: Re: Backtracking in color scanning</i><br>
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<i>>> | MIME-Version: 1.0</i><br>
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<i>>> | =</i><br>
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<p>
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<i>>> | Rainer krienke <<a href="mailto:krienke@mailhost.uni-koblenz.de">krienke@mailhost.uni-koblenz.de</a>> wrote:</i><br>
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<i>>> | > =</i><br>
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<p>
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<i>>> | > I use sane0.62 with my mustek 1200spro (connected to an >ADAPT=</i><br>
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EC 2940<br>
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<i>>> | > scsi adapter).</i><br>
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<i>>> | =</i><br>
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<p>
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<i>>> | Do you mean Paragon 1200SP Pro? How did you manage to make it >wo=</i><br>
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rk with =<br>
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<p>
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<i>>> sane??</i><br>
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<i>>> | =</i><br>
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<p>
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<> =<br>
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<p>
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<i>>> Oh sorry I was "some letters" wrong. I did'nt mean 1200 Spro but >must=</i><br>
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ek 1200 SP.<br>
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<i>></i><br>
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<i>>> Because of the assumption of Roger (<a href="mailto:R.E.Wolff@BitWizard.nl">R.E.Wolff@BitWizard.nl</a> ) who</i><br>
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<i>>> said the backtracking problem might be due to the kernel buffer that</i><br>
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<i>>> has to be copied in user space, I thought that if this is true</i><br>
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<i>>> something should change if I reduce the buffer from 127K to half the</i><br>
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<p>
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<i>>I just use a 1Mb buffer for my scanner. However I had to change a few</i><br>
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<i>>lines in sg.c ...... Ah. I nowadays have the patch ready. Attached. =</i><br>
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<p>
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<i>></i><br>
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<i>>Your "kernel data segment" does grow by a megabyte using this</i><br>
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<i>>patch.... I'm going to submit a slightly more generic patch one</i><br>
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<i>>day......</i><br>
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<p>
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<i>>Using half the size, or even a quarter (32k, default) doesn't help.</i><br>
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<p>
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<i>>We could try to issue the next "read" AS FAST AS POSSIBLE, discarding</i><br>
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<i>>the data just read. This probably requires some serious hacking. =</i><br>
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<p>
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<p>
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<i>>> size. I recompiled sane and my kernel but the effect when scanning</i><br>
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<i>>> colour images stayed the same. Moreover I think because of the fact</i><br>
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<i>>> that other people (running Pentium 200 pro maschines) have the same</i><br>
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<i>>> problem this cannot be due to lack of speed.</i><br>
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<p>
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<i>>A pentium PRO is not much faster on memory limited copies than a</i><br>
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<i>>pentium. (Both use a 64bit main memory link.)</i><br>
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<i>></i><br>
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<i>></i><br>
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<i>> Roger.</i><br>
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<p>
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Thanks for your patch that was includes in your mail above. Sorry I did<br>
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not have the time until now to give it a try.<br>
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<p>
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Well increasing the buffer size in sg.h to a size of 0x100000 really<br>
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helped. The effect that there was too much bacjtracking when scanning a<br>
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color image at say 300dpi has gone. The scantime improved a lot by this.<br>
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It=B4s now comparable to the time a windows twain driver needs to do the<br>
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same.<br>
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<p>
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Thanks =<br>
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<p>
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Rainer =<br>
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<p>
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<p>
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----------------------------------------------------------------------<br>
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Rainer Krienke <a href="mailto:krienke@informatik.uni-koblenz.de">krienke@informatik.uni-koblenz.de</a><br>
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Universitaet Koblenz, <a href="http://www.uni-koblenz.de/~krienke">http://www.uni-koblenz.de/~krienke</a><br>
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Rechenzentrum, Voice: +49 261 9119-641<br>
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Rheinau 3-4, 56075 Koblenz, Germany Fax: +49 261 9119-499<br>
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----------------------------------------------------------------------<br>
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<p>
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<pre>
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--
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Source code, list archive, and docs: <a href="http://www.azstarnet.com/~axplinux/sane/">http://www.azstarnet.com/~axplinux/sane/</a>
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</pre>
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<!-- body="end" -->
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<p>
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<ul>
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<!-- next="start" -->
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<li> <b>Next message:</b> <a href="0146.html">Ignacio Garcia: "Problems with xscanimage (sane 0.63)"</a>
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<li> <b>Previous message:</b> <a href="0144.html">Michael Ritzert: "Re: mustek problems in lineart mode"</a>
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<!-- nextthread="start" -->
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<!-- reply="end" -->
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</ul>
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