So the doe, ray, me, etc, is the semitones? But with probably different spellings. French maybe or Latin?
Those are the seven named (white) notes, which can have either one or two semitones between them & the end "do" an octave higher than the starting one.
Thanks all, for the clearer understanding. And all musical instruments would follow this scheme. Are the guitar strings, and even other instruments, adjusted with 1/12 length adjustments? Or 1/24th adjustments?
Some countries & traditions have other intervals and numbers of notes, but the equal increment 12 semitone one is the commonist in western music - and the nearest to being logical!
Guitars use all twelve semitones with no distinctions, one fret per semitone.
It's down to the tuning of each string as to what the lowest note each can play is.
The commonest tuning has each higher string starting five (or four) semitones higher, a 5-5-5-4-5 pattern, so the high string on a six string guitar is then two octaves, 24 semitones, higher than the low string.
You can see the progressive logarithmic intervals in the spacings of the frets, wide near the head of the neck and narrow at the body end:
What do those piano pedals do?
One is sustain. Each key mechanism normally has a felt pad pressed against the strings it sounds, to mute them, & that lifts when the key is pressed, so the note stops when you release the key.
The sustain pedal lifts all the damper pads so notes are not ended when the keys are released.
Each piano key has up to three strings side by side in the piano frame, normally all struck at the same time by the key mechanism hammer when a key is pressed.
One of the other pedals shifts the entire mechanism sideways slightly so the key hammers only strike one string rather than all.
The third pedal is a variant of the sustain, but only locking the damper pads on keys that are already pressed when the pedal is pressed; those notes are sustained until the pedal is released, while all others still mute when released.