I work alongside a group of engineers responsible for HDD testing, failure analysis and firmware development. One of their tools of the trade is an old radio sh

I work alongside a group of engineers responsible for HDD testing, failure analysis and firmware development. One of their tools of the trade is an old radio shack telephone amplifier with a magnetic suction cup pickup. Using this unit, the engineers listen to the noise coming from the HDD electronics and motors and can identify firmware versions, drive states (like heads parking) and posible timing issues - I often hear discussions like 'this drive must have the r3 firmware mod as the cache preload kicked in slightly later' and 'sounds like this unit has a manufacturer x motor'