 Forth is so named because in 1968 " the file holding the interpreter was labeled <unk> , for 4th ( next ) generation software — but the IBM 1130 operating system restricted file names to 5 characters . " Moore saw Forth as a successor to compile @-@ link @-@ go third @-@ generation programming languages , or software for " fourth generation " hardware , not a fourth @-@ generation programming language as the term has come to be used . 
