Beforehand I'd sent in my CV and approached the company about prospective positions in the future. I was asked to come in and I was sat with a senior consultant (was also the CTO) and then asked questions about my experience, and then skill probing questions such as what I might expect to see on various types of system. The questions covered a wide variety of platforms and the interviewer seemed to want to get a feel for my depth and specialisation of knowledge rather than expecting total complete knowledge of everything - obviously they were also noting my reasoning and interpersonal skills at the same time.