Your Sun can't remember host-id, date, mac-address? Thats mostly a broken nvram - the integrated battery has reached the end of its life. You can either buy a new one, or fix it yourself :)

The nvram chip (refer to to your Systems Handbook for position) consists of three parts: the bottom layer is the chip itself, over it are a oscillating quartz on the one side and the battery on the other side. Take something like a dremel and cut the battery off. Be careful! Now take a 3V lithium battery and solder it with 2 cables on the chip. That will last forever ;)

Here is a pictured guide for that "operation" taken from www.mnvo.de. It should be easy to understand even though its in german, just follow the pictures and figures.