Just to comment about sysread(). If I'm not wrong, for sockets you can't try to read more than 1024*8 bytes per time with sysread()! At least with Perl-5.6.1 the bug exists. But since you are using the system resource I don't know if this is really a bug.

Soo, for portability use read(), and you will ensure that you are reading all the data. (As documented in the Perl POD).