About six months after I started, they replaced all of the POS terminals that had been there since I began with new shiny ones.
New shiny ones that were dumb terminals to virtual Windows XP instances running out of the back office. Unfortunately, there were approximately 20 POS terminals in the place.
And every single one of them was on the same collision domain. All the Cat5 was ratnested under the counters; some of them were held in to the plethora of cheap 5-port hubs by duct tape. In the networking cupboard behind concessions, the wires were coated in old "butter flavored topping." Occasionally, all the POS terminals in the box office would cut out - usually because someone in the back office accidentally knocked over the five-port hub back there, and one of the connections fell out.
Needless to say, management was super excited to have these shiny new POS terminals. Everyone who had to use them? Well.. we all did our jobs a little bit slower: it's hard to ring up a ticket sale when it takes 3-4 seconds for a touchscreen press to register. The actual hardware of the POS terminals was pretty (needlessly) impressive. A lot of times the people running a place really have no idea what any of "that computer stuff" does - they rely their POS salesman and their crack team of installation specialists to get everything running. And from what I gather, a lot of those companies are pretty much used car salesmen...
(wonder if that's a potential business op? It's a hard market, to be sure, but most store owners I know that use a POS hate the system like they hate fleas, mosquitos, and AIDs)
Looks like someone else has developed it: http://www.crunchgear.com/2010/04/27/the-ipad-pos-system-com....
In most of those settings (read: no need for remote access) it is per se not worse than deploying Linux unless you have them connected to an open LAN/WLAN and/or the Internet.
It sure made sense for a lot of people during the last 15 years for various reasons, occasionally one can even spot a DOS system still being used (now you know why they still sell floppy disks in 2010).
Big companies like McDonalds clearly had the resources long ago to go for a different approach but only during the last 5 years or so this has become a more viable option for many small-medium shops.
Even though Ubuntu, Google, Wikipedia & Co have "happened" during those Windows POS years we aren't there yet.
I suspect mainstream small-medium business will skip this step anyhow:
For example I myself am working on a distributed POS solution using a certain set of 2010 state of the art technology (the no-brainer variation: "cloud" back end and administration, newest generation of touch devices as "terminals").
It allows for low on site IT infrastructure and maintenance plus a strong emphasize on UI/UX which thanks to Apple is finally becoming ubiquitously expected.