- xscanimage/xcam crashes X server on Linux/Alpha
        Older versions of the TGA X server (such as version 3.1.2) are known
        to fail when creating shared images of certain sizes.  This can be
        avoided by invoking xscanimage and xcam with option --no-shm.  

- In three-pass mode, the progress indicator is not updated correctly. This
  just menas that scanning is faster than the disk can handle. It happens
  especially in three-pass mode because much seeking is going on in this mode.
