This is the Mac OS X beta driver for Realtek RTL8139/810x Family PCI Fast Ethernet NIC. This beta driver is for Mac OS X 10.1 or newer versions. If your Mac OS X is 10.0.4, please download the driver for Mac OS X 10.0.4 from http://www.realtek.com.tw Please follow the following instructions to install the driver: 1. Decompress the rtl8139.tar with the "tar" command in Mac OS X. tar -xvf rtl8139.tar Then the rtl8139.pkg folder containing the driver package will be created. 2. The rtl8139.pkg folder is shown as a single item in the Finder window. Please double click the rtl8139.pkg item, then the installer will be launched. Please follow the installer instructions to finish the driver installation.