BIOS is the software that initializes the computer hardware and then boots the operating system.
CMOS in this context means the 128 or 256 bytes of battery-backed-up RAM that holds the state that was configured through the BIOS setup menus (or biosconfig).
IPMI is a standard interface used to manage servers. For more information, go to: http://www.intel.com/design/servers/ipmi
ipmitool is an open-source tool used to manage a system. ipmitool is distributed on the Tools and Drivers CD for each Sun platform. You can find documentation (for example, on the ipmitool chassis bootdev command) at: http://ipmitool.sourceforge.net/manpage.html.
NVRAM in this context means the portion of the BIOS ROM that holds the BIOS’s boot information.