Yes, TWAIN will work in Vista.
(Note: the following are not product endorsements; just speaking from direct
experience with a couple scanners)
Although the steps differ from vendor to vendor (and often model to model
for the same vendor), here's what I do to install the drivers for an Epson
Perfection 1200 Photo:
Download the latest XP driver package from Epson's website
Run the self-extracting exe (uncheck "When Done Unzipping Run: Setup.exe")
Go to the new directory, open the properties dialog for Setup.exe and select
XP SP2 compatibility (this isn't necessary for all installation packages, but
it's necessary for this particular package)
Run Setup.exe
Connect a USB cable and turn on the device
Allow Vista to "Locate and install driver software..."
Select "Install Anyway" when it warns of an unsigned driver (this is
perfectly safe in this case because it uses the in-box usbscan.sys driver)
As an example of how different the process can be for another device, I have
to do the following for a CanonScan FS 4000 US:
Download the latest XP driver package from Canon's web site
Run the self-extracting exe (this just places files in a directory... no
installation done yet)
Connect a USB cable and turn on the device
Allow Vista to "Locate and install driver software..."
Select "I don't have the disc. Show me other options."
Select "Browse my computer for driver software..."
Browse to the location where the files were extracted
Select "Install anyway" (once again, perfectly safe because it uses
usbscan.sys)
(For anyone who actually has an FS4000US, also download and install the
v1.04 patch after successfully installing the v1.03 drivers. Unplug the
device before installing the patch.)
So, in general, follow the same steps you would on XP. If the setup program
fails, try enabling the XP SP2 compatibility. If the device is based on an
in-box driver like usbscan.sys, it's safe to install in spite of installation
warnings.
--
David Goll
Windows Portable Devices Team
This posting is provided "AS IS" with no warranties, and confers no rights.