Re: HP PhotoSmart S20

From: Adrian Perez Jorge (
Date: Sun Dec 31 2000 - 09:10:21 PST

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    ('binary' encoding is not supported, stored as-is) Yes, it's fun...and _hard_. Go to

    and run USB Snoopy in your windoze. Try to do some scans and save the
    log, each one in a different file. Do a scan in black&white, another
    in colour, using the same scanning size (if applicable) and another
    pair of scans using a different size. It's not necessary to wait
    until the scanning is finished. You can just stop the log after some
    centimiters (or half inches :) are scanned.

      Then put those files in a web site, and the original image aswell.
    Explain the resolution, size and color depth of each scan. Oh... I
    forgot: compress all files!, but images shouldn't be saved in a
    non-destructive format like jpeg.. use png/tiff/...

       Put also a description of the machine that will be used for
    testing: number of processors, motherboard, if the USB chipset is UHCI
    or OHCI based, processor speed. Linux kernel version is also very

       It is also useful (but not suggested) to open the scanner and
    annotate the name/number of all big chips you can find. Also it can
    solve some problems to dissasemble the windoze driver, which is used to
    reside in c:/windoze/system32/drivers with extension .sys and a name
    wich in some way is related to the name of the scanner. You can use
    the (nice) Sang Cho windoze disassember under linux. Get it at

       And finally, let's see how fun will be this... ;)

    PS:if you have any problem in any of the above steps, e-mail me or
    post in the list (if the comunity is interested in that).


    Adrian Perez Jorge
    adrianpj at

    >Hi Monty,
    >this is not easy. You will get no documentation for the S20 from HP. And
    >it seems that it is not compatible to some other scanner. You only could
    >reverse engineer the Windows driver or have a look at the USB protocols
    >generated by some USB spy software. And you have to build a backend from
    >scratch (or use the ppm-backend as example). And your scanner may crash
    >during your tests.
    >But it could be fun. I suppose other backends have been written this way
    >Happy new year.
    >Monty Taylor wrote:
    >> Hello,
    >> Is anyone working on a backend for the HP PhotoSmart S20 USB? If not,
    >> (or if so) could someone point me in the right direction so I could work
    >> on one? (or help out) I'm scanning negatives on my wife's windows
    >> machine right now and it's driving me NUTS!
    >> Thanks for the help...
    >> Monty

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