ALT An alternate title for this post might be, "Twitter has a kernel team!?". At this point, I've heard that surprised exclamation enough that I've lost count of the number times that's been said to me (I'd guess that it's more than ten but less than a hundred). If we look at trendy companies that are within a couple factors of two in size of Twitter (in terms of either market cap or number of engineers), they mostly don't have similar expertise, often as a result of path dependence — because they "grew up" in the cloud, they didn't need kernel expertise to keep the lights on the way an on prem company does. While that makes it socially understandable that people who've spent their career at younger, trendier, companies, are surprised by Twitter having a kernel team, I don't think there's a technical reason for the surprise. Whether or not it has kernel expertise, a company Twitter's size is going to regularly run into kernel issues, from major production incidents to papercuts. Withou...