The problems posed were all "gotcha" type problem where either you'd read the solution or you'd most likely end up with a decent but suboptimal alternative, or where the recruiter asked for knowledge about toally obsolete things (e.g. I was asked about the structure of an inode in UNIX v6 - I told him I didn't know it but gave a general response about the type of information Unix-y systems keep in inodes, and with more detail about Linux; to add to it, for the role in question a knowledge of filesystem details was irrelevant).
Companies badly need to train a pool of interviewers, and track what kind of questions get asked and provide feedback on it. The vast majority of companies I see have a hiring process where some or all of the technical questions are down to the pet peeves of the interviewer or their manager.