The rain in TWAIN falls mainly in the SANE?


If you've ever used a scanner in Windows or MacOS, you're likely at least somewhat familiar with the TWAIN device. You'd select it from the Import menu in your imaging application and it would run the scanner's application to preview/acquire the image.

Linux doesn't use the TWAIN API, it uses the SANE (Scanner Access Now Easy) API.
     for those curious, TWAIN doesn't stand for anything, but rather comes from Rudyard Kipling's 
     "The Ballad of East and West" - "...and never the twain shall meet...", reflecting the difficulty, 
     at the time, of connecting scanners and PCs. The TWAIN group uppercased it to 
     make it more distinctive, but its not an acronym, although "Technology Without An Interesting Name" 
     is suggested. 

Linux uses SANE for two reasons:
TWAIN does not separate the user-interface from the driver of a device, preventing network transparent access to image acquisition devices.
Due to this, the TWAIN drivers are tied to a particular GUI API, which would be unreasonable in a Linux environment.