Why std.stdio and not std.io ?

[Walter Bright]

Tom wrote:
> Maybe it sounds as a stupid question but I still wonder why to mimic C include
> name for standard input/output.

'std' is the package for standard D library functions.

'stdio' is the module for accessing the C standard I/O streams stdin, 
stdout, and stderr.

std.c.stdio is for access to the C <stdio.h> functions and declarations.

So the std in std and stdio are two different meanings of 'standard'.