I'm surprised more people aren't mentioning this. I have a FiiO X3. It plays pretty much all hi-res audio files, it can be used as a DAC, it has some internal storage with a MicroSD slot, and it's a fraction of the cost at around $200. Even the newer, more powerful X5 with dual MicroSD slots is $349 on Amazon. The new Sony Walkman seems rather pointless.

I read it the same way. This is a poorly worded title.

I change the "stations" ON the radio. I don't actually change the radio itself, which is more what these guys are doing.

This is a broad topic, but I would say begin by identifying your single points of failure. You can then research setting up HA solutions for each of those resources. Also, understand the difference between high-availability and load balancing. Just because your database is fault-tolerant, it does not necessarily mean it can scale to cope with increased traffic.

Draw a high level map of your application and all the server/network resources it uses. Take each one of those components and analyze them for load balancing and fault tolerance. Any single component failure should not affect the overall uptime of the application. Part of a high-availability system is having proper monitoring and notification tools in place. It takes a lot to make a high availability environment work and some of it is not engineering related, but business process related. If your servers are in a data center and a database server goes down, yet your notification system sends an email to a database developer who works 9am to 5pm (maybe on vacation) alerting him/her of the issue... You can see how this can lead to problems. Proper health checks, escalation paths, etc. are all part of making your system work.

My $0.02.