I know this is a popular piece of software and I'm sure a lot of SGI users are running it ... be aware that there is a serious security hole in versions below 2.2.8.
SGI has posted a beta tardist online:
There is also a tardist available direct from samba.org:
I'm uncertain what differences, if any any, exist between the two distributions.
(14th Mar, 2003) Security Release - Samba 2.2.8
A flaw has been detected in the Samba main smbd code which could allow an external attacker to remotely and anonymously gain Super User (root) privileges on a server running a Samba server. This flaw exists in previous versions of Samba from 2.0.x to 2.2.7a inclusive. This is a serious problem and all sites should either upgrade to Samba 2.2.8 immediately or prohibit access to TCP ports 139 and 445.
See http://us1.samba.org/samba/samba.html for more details.