Okay, let's say the cache is cold and you're on an old clunky spinning rust 5400 RPM hard drive. Do the math. How long will it take, worst case, for the platter to spin to where calc.exe is stored?

For a 5400 RPM drive, worst-case rotational latency is one full rotation: 5400/60 = 90 rev/sec, so ~11ms. Average is half that (~5.5ms). If you also need to seek (yes, we'll definitely need to move on both axes in the worst case scenario requested, likely all the time), 2006-era datasheets show average seek around 11-12ms, with full-stroke seeks around 21-22ms. So worst case total access: ~33ms.

Seagate Momentus 5400.3 manual (2005): https://www.seagate.com/support/disc/manuals/ata/100398876a....

Hitachi Travelstar 5K120 (2006):http://www.ggsdata.se/PC/Bilder/hd/5K120.pdf

WD Scorpio (October 2007): https://theretroweb.com/storage/documentation/2879-001121-a1...