The phrase originates with the ‘BUGS’ section of the 4.2BSD man page for the `tunefs(8)` command, for the Berkeley Fast File System that is the topic of the OP article.

This, but in true to form HN style, if you don't recognise the reference, it's psychologically safer to down vote what you don't know.

Even if you do recognize it, this isn’t Reddit.

/r/confidentlyincorrect

karma worth a little on the influencer age

tuna fish

Tune-a-fish

EDIT: looks like there’s a bit more to it https://unixhistory.livejournal.com/1808.html

It's a reference to a joke by the comedian Groucho Marx (1890-1977) "You can tune a piano but you can't tuna fish" (also a title of a 1978 REO Speedwagon album paying homage to Marx who had recently died). It's a pun on "tune a" and "tuna".