The Development of the C Language (2003)

After a rapidly scuttled attempt at Fortran, he created instead a language of his own, which he called B. B can be thought of as C without types; more accurately, it is BCPL squeezed into 8K bytes of memory and filtered through Thompson’s brain. The original BCPL compiler was transported both to Multics and to the GE-635 GECOS system by Rudd Canaday and others at Bell Labs [Canaday 69]; during the final throes of Multics’s life at Bell Labs and immediately after, it was the language of choice among the group of people who would later become involved with Unix. For example, the that escapes from a BCPL statement was not present in the language when we learned it in the 1960s, and so the overloading of the keyword to escape from the B and C statement owes to divergent evolution rather than conscious change.

Source: www.bell-labs.com