explorer is s Sun Service tool for collecting system configuration information about your machine. It is very useful when you need to open a service request with Sun.
If you save the explorer outputs, they are also very useful for helping you to find out how the system used to be configured, to help you to investigate a change (or series of changes over time), or return your system to a previous configuration.

However, for finding the serial it is less useful because as Dragon wrote, "install and configure explorer . Configuring it includes telling explorer what the serial is, so that you can look it up later when you need to know.

This will not solve your current problem.

Dragon's other ideas may do more for you:

This is a very good idea, and might even help you because the most recent sneep update allows sneep to find the serial number for you on some of the recent Sun and x86 platforms. If you have recent hardware, this might get you the serial for many of your machines.

For older machines without built-in serial numbers, there is no choice but to have someone look at the serial number on the actual machine and tell sneep what the serial is one time. After that, sneep can tell you whenever you need to know.

Sneep can also keep track of other things that might be important to you, like the machine's rack location in the data center, support contract number, the serial number of the attached storage devices, etc.

In any case, if you use sneep, sneep will keep the serial number updated in the explorer configuration file for you.

This may be a very good idea for you too, if you have a number of machines to keep track of. The doohick is called Sun Inventory Connection

As far as the serial number goes, the inventory connection uses a package to find the serial number which gets most of its information from sneep, so sneep is still your best thing to do.

explorer, sneep and the Service Tags used by the Sun Inventory Connection are all bundled together in one easy-to-install download called the Sun Service Tools Bundle (STB) By June 2008, you should be able to find STB3.x or newer at Sun Services Tools Bundle . If you are too early for that, get STB 2.0.