Turns out googling for "8½ window system" gives no results (although Google's KI has this to say 'Based on the search results, "8½" refers to the Windows 8.1 up

Turns out googling for "8½ window system" gives no results (although Google's KI has this to say 'Based on the search results, "8½" refers to the Windows 8.1 update, which was released in 2013 to address critical user feedback regarding the original Windows 8') However googling for "8 1/2 window system" leads to a proper page about the 8½ window system https://9p.io/sys/doc/8%C2%BD/8%C2%BD.html https://9p.io/sys/doc/8%C2%BD/8%C2%BD.html