Sampo Kuokkanen
Hi Taiwan! My name is Sampo Kuokkanen and I currently live in Osaka, Japan, but I'm originally from Finland. I lived in Taiwan for three years, so I can speak a bit of Chinese too.
I work as a Ruby on Rails developer and I'm also the head of the Japanese office for Evil Martians, keeping everything going here in Japan. I recently started looking at JRuby after Charles Nutter's talk in RubyKaigi 2026 and I'm planning on talking about that and the larger testing area of Ruby.
Session
Ruby has multiple implementations. CRuby (the canonical "MRI") is the reference, but JRuby (now at Ruby 4.0 on the JVM) and TruffleRuby (at 3.4, with 4.0 underway on GraalVM) are real, production-grade alternatives. They aim to run the same Ruby code, so your gems, your Rails apps, your scripts. But they're written in different languages, on different VMs, with different internal data structures. So how do they agree on what Ruby actually is?