My guess, and paraphrasing: it's like software that blocks out distractions. No modern web, he stays mostly focused on his job, which is writing. The software w

My guess, and paraphrasing: it's like software that blocks out distractions. No modern web, he stays mostly focused on his job, which is writing. The software works in a way that suits his sensibilities - consistent, minimalist, quirky, undistracted by FB and Youtube. "More UNIX than UNIX", if you will. Some people eat aeroplanes. He uses Plan9.