According to Dennis Ritchie's 1993 paper The Development of the C Language:
Also during this period, the compiler was retargeted to other nearby machines, particularly the Honeywell 635 and IBM 360/370; because the language could not live in isolation, the prototypes for the modern libraries were developed. In particular, Lesk wrote a ‘portable I/O package’ [Lesk 72] that was later reworked to become the C ‘standard I/O’ routines.
The reference [Lesk 72] may be an error, since it is given in the references section as [Lesk 73]:
M. E. Lesk, ‘A Portable I/O Package,’ AT&T Bell Laboratories internal memorandum ca. 1973.
I cannot find any copy of this memorandum anywhere; given it was an "internal memorandum", I assume it is not publicly available (if it survives at all). But, I am wondering, in its absence, if there are any public sources on the details of Lesk's package, and how it differed from later <stdio.h>?
