This image shows the layout of the servers and switches in a full rack. From the bottom to the top of the rack, the layout is as follows:
Power Distribution Unit-B
Power Distribution Unit-A
Sun Datacenter QDR InfiniBand Switch (rear), 1U Vented Filler (front)
U1 to U13: Big Data Appliance Servers, numbered from 1 through 9
U14 to U19: 1U vented filter
U20: Sun Network QDR InfiniBand Gateway Switch (rear), 1U Vented Filler (front)
U21: Cisco Ethernet Administration Switch (rear), 1U Vented Filler (front)
U22: Sun Network QDR InfiniBand Gateway Switch (rear), 1U Vented Filler (front)
U23 to U42: 1U vented filter
U1 to U13: PDU A input 0, PDU B input 2
U14 to U28: PDU A input 1, PDU B input 1
U29 to U42: PDU A input 2, PDU B input 0