The power modules that are installed on the chassis. The power modules are listed as a bitmap. The bitmap is a string containing a list of 1's and 0's that is as long as the number of power modules supported. If a power module is installed in a bay, a 1 is present in the string in the position representing the bay ID as read from left to right. For example, if power modules are installed in bays 1 and 3, and 4 power modules are supported, the string would look like '1010'.