Background history – Between 1968 and 1970 Vercoe works at Princeton University where he developed the Music 360. In 1971 he moved to Massachusetts Institute of Technology (MIT) where he founded, two years later, the Experimental Music Studio (EMS) and where he completed the Music 11. Veroce initially wanted to make an updated version of Music 360, but in the end, he created a whole new software, which is characterized by important differences compared to its predecessor, although the similarities were equally important. The name Music 11 derives from the new machine adopted: the PDP-11 computer. In fact, The Music 11, is also known for being the first new type of software for minicomputers (as opposed to the mainframe) that were distinguished in the architecture, size and cost.
News – Before Music 11, the Music 360 was highly regarded for its capabilities, so as to be used far longer than the same Music 11. The new software, however, introduced some very interesting news: just think that many elements of Music 11 will then be reused in Csound. Among the most important should be emphasized the rehabilitation of units generator (UG) dedicated to signals filtering. It was characteristic that Max Mathews had ousted with the Music V. Vercoe inserted units capable of working as high-pass, low pass, band-pass and band-limit filters.
Audio Rate/Control Rate – Probably the most important news, for the next developments, was the distinction between audio and control signals. The Music 11, in fact, was designed to distinguish between two different types of processing (audio-rate and control rate), each with a different sampling rate. Today the distinction between these two signals has become commonplace, but in those years, however, it was an important aspect of allowing a considerable saving of resources for the computer, resulting in higher performance than ever would be achieved by using, on the same machine, programs without that distinction. This results in unnecessary fatigue processor, since the control signals could be generated at a lower frequency audio signals, saving work on a computer processor and consequently with better performance.
OEDIT – Equally important, among the new features, was the work done on the communication between user and machine. Vercoe, as it did Max Mathews with Music IV, devised a graphical data entry program developing Oedit (EDITOR Orchestra). Thus, it was possible to create your own algorithms manipulating on-screen graphic symbols representing the opcodes used by the Music 11. Once processed with Oedit, algorithms were translated into alphanumeric values, according to the syntax of Music 11. Oedit was a software with many limits but still contributed to speed up computer programming. In the realization of Oedit, moreover, Vercoe was also supported by Miller Puckette; years later, he referred to this experience for developing the graphics system for MAX.
Subsequent developments – The Music 11 closes the first phase of research by Barry Vercoe in the following years will work to develop a system for man-machine interaction in live performance: the Synthetic Performer. The development of the latter, together with the innovations introduced with the Music 11, will be important for the realization of Csound.
For this topic I’ve read.
 Barry Vercoe, Computer System and Languages for Audio Research, The New World of Digital Audio (Audio Engineering Society Special Edition), 1983, pp. 245 – 250.  Miller Puckette, Max at Seventeen, Computer Music Journal, Vol. 26 , 2002.