The talk at the FOSDEM conference focused on a specific machine called the Gamma-3, which was a first-generation computer developed in the 1950s. The speaker discussed the historical context of the machine and its architecture, including its use of vacuum tubes and delay lines for memory. They also explained the instruction set and the limitations of the machine. The speaker then talked about existing emulators for the Gamma-3 and detailed their own emulator and what they have learned from it. They mentioned the challenges of simulating the reading of the core memory and the possibility of developing a compiler for the Gamma-3. Overall, the talk provided technical insights into the Gamma-3 and its significance in the history of computing.