The System ID uniquely identifies a particular computer. On Irix platforms this is the sysinfo that can be found by opening a shell window and typing: sysinfo On Linux platforms this is the MAC address of the eth0 Ethernet adaptor of your machine. This can be found by opening a shell window and typing: /sbin/ifconfig eth0. The sysID is the HWaddr: xx:yy:zz:aa:bb:cc part of the output.