Barcode support? This is an issue that is important and must be addressed by many businesses looking into a modern POS system.
In Linux, many barcode readers are actually treated as keyboards. Despite not appearing anything like a PC keyboard visually to us humans, many hand held barcode scanners actually are seen by the Linux operating system as a keyboard (and they work out of the box because of this fact). This said, when purchasing a barcode scanner for Linux based POS systems, it never hurts to ask if they are natively supported, just in case.
Linux POS systems a workable solution? Absolutely yes. As a matter of fact, you would be surprised how many small businesses in your area may already be using them and are not even aware of it.
Is Desktop Linux ready for small businesses?
Based on everything presented above, is it fair to say that a small business can operate exclusively on a Linux workstation/server setup? The short answer is yes. The longer, more in-depth answer is yes with the help of professionals to assist the small business owner with setup.
To a growing degree, open source/Linux consultants will play a growing role in enabling small businesses to free themselves from the ugly clutches of vendor lock-in and proprietary file formats. Despite my earlier complaints about Open Office not defaulting to the proprietary Microsoft Office file formats, the truth of the matter is that it is healthier to embrace the non-proprietary every chance we can.
To understand why this is, simply ask someone with MS Publisher 2000 installed to go ahead and open up the Publisher file created with the version from 2002. That's right, it will not happen. Hence the importance of not becoming a victim to closed source software.
Yes, there is no question at all that Linux is suitable for thousands of different small businesses out there. The bigger hurdle, however, is locating someone competent enough to enable those small businesses to make the switch once and for all.