Yes, back then (2005) I didn't know about ABC nor Lilypond (which I've started using since end of 2011, month after end of my music prototyping Ask HN thing: https://news.ycombinator.com/item?id=3089259, which will hopefully get some follow-up in the future).
To be honest, today I would slightly change my notation, to make it more readable, consistent and friendlier for English-speaking people:
OTD[.]
O - octave: [0-9]
T - tone: C,d(es),D,e(s),E,F,g(es),G,a(s),A,b(es),B,P(ause)
D - duration: [0-9A-Z] meaning:
breve (double whole note) // for D==0
1/D note // for D!=0
. - dotted note, changes duration to: // d - duration
d(2 - 1/2^n) // n - number of dots
To be honest, today I would slightly change my notation, to make it more readable, consistent and friendlier for English-speaking people:
Same fugue would start like: which is so much more better...Why I didn't do it like that from the beginning? No idea...