Actually, this has to do with the DBI module (I assume the db is a SQL-type?). Everyone else who has responded is correct: Perl does not double-interpret strings. In the case of DBI, however, Perl is passing a string to a database, which uses backslash for its own purposes (e.g. to escape '%' and '_', usually). As such, the database needs its own set of double backslashes so that it operates correctly.

An example:

my $string = "C:\\\\WINDOWS\\\\Desktop";
# $string is stored as "C:\\WINDOWS\\Desktop"
DBI->somemethod($param1, $string);
# Equivalent to DBI->somemethod($param1, 'C:\\WINDOWS\\Desktop')<BR>
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Hence, the quadruple bachslashes are needed because we have two programs, Perl and database, that need them escaped.