Small bumps on certain keycaps to keep touch-typists registered. Usually on the 5 of a numeric keypad, and on the F and J of a QWERTY keyboard; but older Macs (like pre-PC electric typewriters) had them on the D and K keys (this changed in 1999).
Small bumps on certain keycaps to keep touch-typists registered. Usually on the 5 of a numeric keypad, and on the F and J of a QWERTY keyboard; but older Macs (like pre-PC electric typewriters) had them on the D and K keys (this changed in 1999).