Vitanuova for 2001 September 5

Wednesday

I had lunch with Biella and Ren, and dinner with Ren.

"A ... side ... channel ... attack ... against ... the ... human ... mind!"

Much techne.

I have a lot of things I need to do.

Arms

Pretty sore again. One of the things I should do is do something about that. Whenever I think of my arm injury, these days, I think of the song: "It's not going to stop / 'Til you wise up."

A scary Unix command

tail -f /dev/zero &

Don't try this at home!

I accidentally rendered a system (temporarily) unusable with this simple command. That was no fun. It could probably have been avoided with stricter ulimit settings.

tail will ask for so much memory that the kernel will try to swap out almost everything else to accomodate it. And most of its time will be spent in I/O, so a lot of CPU time will be spent in kernel space answering useless requests for blocks of zeroes.