Thank you for your help. Ultimately, I found a hint at http://perldoc.perl.org/perlfaq6.html describing a method on file streaming. The specific code example I ended up studying (took me about three hours of reading to figure out what (?s) did. Another hour to figure out why $_ needed to be localized.) is:

    local $_ = "";
    while( sysread FH, $_, 8192, length ) {
        while( s/^((?s).*?)your_pattern/ ) {
            my $record = $1;
            # do stuff here.
        }
    }
[download]

Yes, I know the bug in this example. It's exactly how it is on the perldocs. Took me about an half hour of debugging to figure it out. Just about drove me nuts.
In any case, many thanks for the pointers, tips and hints. I needed some starting points and that is exactly what I got.