Quoting Andrew Greig (pushin.linux@gmail.com):
My question was how can a proprietary product, completely stand-alone in my ~/ , load in seconds, and discover the SCSI card in seconds, and be ready to work? Xsane, when installed into a running machine has always needed a reboot to start working. In fact if I cancel a scan (I have learned not to do this) Xsane will not even find the scanner until I reboot. This provokes another question, how do I avoid the reboot to get a SCSI scanner working again? Is there such a thing as stopping and starting a SCSI process?
Here's more information about SCSI rescanning in Linux: http://linoxide.com/how-tos/linux-scan-scsi/ Quite possibly, Vuescan includes wrapper code to trigger a rescan at the time of program startup. I haven't personally needed to do scanning on Linux (or, frankly, any other OS) in far more years than I'd really like to think about. At the time I last did, I used whatever was then common on Linux and an old SCSI-based flatbed scanner. It worked in the routine way one would hope and expect, and I certainly never had to reboot just to make the software find the device.