ABC Notation is as much a computer language as it is as form of music notation. It was originally designed as a way, using basic typeable computer characters, to display songs that traditionally would be found using the standard music staff. While its use is limited, it has been popularized in part due to a number of freeware tools to work with it.
ABC Notation was invented by Chris Walshaw in the 1980s. Eventually Walshaw created a front end for converting ABC Notation documents into standard notation using TeX a freeware typesetting program. The intended audience was folk musicians, and musicians who only required a single staff’s worth of notes. Since this time many programs have added support for this notation, and tools have emerged to enable musicians to collaborate using ABC Notation. That said ABC notation still can only contain one stave of notes.
ABC Notation remains a popular tool for musicians. Though mostly a niche tool, ABC delivers what it needs to musicians able to fit their songs into this format. Recent efforts have increased to enhance ABC Notation, and Walshaw has stepped up efforts to unify the myriad applications that use it, and to standardize many of the enhancements these applications have added.
The following are additional resources regarding ABC Notation.