Dennis Ritchie's first C compiler - on Github

DEC computer with DECtape media

Last1120c and prestruct-c were posted on Github - the earliest versions of the very first C compiler in history. The code was written by Dennis Ritchie himself in 1972-1973.

Compilers were found a few years ago on an old DECtape magnetic tape inserted into an antique VAX VAX computer.

Dennis Ritchie is known as the creator of the C programming language and the key developer of the UNIX operating system, which made an invaluable contribution to the development of computer science and computer technology. Unfortunately, most of us realized the greatness of Ritchie’s merits before humanity only after his death in 2011.
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As the author himself wrote in the history of the creation of the C language , the key years were the years 1972-1973: it was then that the transition from typeless B to weakly typed C occurred, with the transition stage NB. None of the previous languages ​​has survived to this day.

Early versions of the first C compiler could hardly be compiled into itself using early Unix emulators for the PDP-11 . Nevertheless, the compiler itself today is completely unsuitable for use, it is of exceptional historical value.

In addition to the coil with the code last1120c, the tape with the code prestruct-c was found, this is a preliminary copy of the compiler before making changes to the structures. The early compiler does not know anything about structures, the struct string does not appear anywhere. In the last1120c version, the structures appeared, but the syntax is very different from modern C and even from K & R I (early version C). In general, it is a very ancient relic.