Why was this datatype signed? Low memory era? Early days of IBM EBDDIC character set that only went from 0-127? (pre-ASCII, pre-ANSI, pre-UTF8)
Clearly from the name the char datatype had to have been meant for characters.
Just seems like a weird oddity and I can't think of very many situations where you would actually want signed char as in "char" instead of unsigned char ... unless you are in 1979 writing Asteroids or something but I bet those days probably used machine language.
Then again, considering the farther one goes into the past, the more important ASM and such become, maybe this has to do with registers.
/May self-research this ... probably will.