Missing some points
"upgrade from xp embedded to 8.1 embedded a known upgrade path"
Known, yes. Easy, no. For a start, it means a complete hardware refresh because the hardware capable of running XP will barely run 8.1, if at all. And there is no upgrade install, 8.1 has to be installed from scratch. The latter will probably be done anyway as it is much easier to image a 8.1 install.
There's another significant difference: for Android you can use something slightly more powerful than a Raspberry PI (you're driving a keyboard, card reader, a screen, a network card and a cash dispenser for essentially a dumb terminal functionality, how much CPU and RAM do you need for that?) vs. a full fledged Wintel box for 8.1
"re-certifying a totally new OS and rewriting all the software from scratch?"
Not sure of the details, but I think that certification has to be done anyway unless the exact same software and hardware is used, which is not going to happen (see above)
As for rewriting the software from scratch, it has to be done if/when the old software was written using a technology no longer supported. Which given the list of abandoned Microsoft technologies of the last decade, that is very likely the case. So a rewrite is already in the cards.
"all to save possibly £20-£40 per machine for a windows licence?"
I think that when you add up the hardware savings, the license savings, the support savings, plus the hardware independence and the freedom to go on your own schedule for updates that's a bit more than a couple of tenners. More like a couple of thousands. Multiply that by the number of ATMs to be upgraded and here's your nice holiday.
NCR is making a clever move.
Biting the hand that feeds IT
