Why is the DOS path character "\"? (2005)
In addition to its use as a path separator in DOS and Windows, the backslash character itself is also interesting because it is very likely a modern invention, with the first attestation in 1940s (!). Its original use in ASCII (1960s) was for ALGOL operator digraphs `\/` and `/\`. Its early use as the C escape sequence (1970s, replacing `*` in BCPL) suggests that it carried no significant semantics at that time.