MCS? This meant "Microcomputer System" back in '76(*). This is from a preliminary copy of an MCS-85 User's Manual I have (another copy I have, from '78, belonged to a former colleague, Jim Porzak, who had a photo of himself & Bill Gates on his office wall! Our company was the Microsoft distributor for Europe at that time - early '80s!). BTW, the Eprom described in the book is an 8708 (8192-bit) device!

Regards,

Richard