I found this surname from a name 'John Salwitz',one of the game designer of game 'PAPERBOY' by ATARI.
I guess this surname's origin is POLISH, JEWISH, or GERMAN;
because I found this surname's suffix '-witz' is a Germanized spelling of Polish surname suffix -wicz (and other slavic surname suffixes),
and probably jewish people use that suffix when they immigrate to Eastern European countries including Poland and other European countries including Germany.....
..... but it's just my guess.
does anybody know SALWITZ's real origin and meaning and respond it?
(sorry for the long sentences.....)