===Node numbers=== All nodes in a Nimbus cluster have an associated number. The number of a node is assigned at boot time by **bpmaster**. In turn, **bpmaster** determines that number by looking up the slaves MAC address in the node lines of __/etc/beowulf/config__. The Master is assigned the node number -1 for consistancy. ===Nodespecs=== Many commands in Nimbus call for a specification of the nodes affected by a command. The nodespec is a standardized syntax for that list which will work with all of those functions. A nodespec element is either a single node number (5), a range of numbers seperated by a hyphen (2-6), or a status specification. Status nodespec elements allow a command to affect all nodes in a particular status. The names are fairly self explainatory: **all**, **allup**, and **allerror**. A nodespec is one or more nodespec elements seperated by a comma such as 1,2,4-10,12,23-30 ===Node names=== beo_nss automatically provides hostname lookup for a node specification in the form n where is a node number. Thus, ping n1 is a valid command to ping 192.168.1.11. n-1 will translate as 192.168.1.1. **NOTE**: There are a few programs (notably telnet) that bypass nss when doing a host lookup. They will not work correctly with the n style node names.