C trivia - was Re: Dennis Ritchie has died

ben wrote: everybody The PDP-10's native character sets are 7-bit ASCII (originally the 1963 edition) packed five characters to a word, with a leftover bit, and "SIXBIT" which is the 64-character printable subset (not including the lower-case region), packed six character to a word (or sometimes three characters to a half-word). The C standard requires that the character data type fit in a byte (ISO/IEC 9899:1999 sections 3.7.1 and 5.2.1), but byte is simply defined as a unit of data storage large enoguh to hold any member of the basic character set, so that is a tautology. However, the standard also requires that the character type occupy at least 8 bits, that the minimum range for unsigned char is 0 to 255, and that the minimum range for signed char is -127 to +127 (section 5.2.4.2.1). This rules out the use of 6-bit and 7-bit characters, so the native PDP-10 text representation cannot be used as the C standard character type at all.