GLYPH<SM590000> Depending on the configuration, two or four intelligent Power Distribution Units (PDUs) are  mounted vertically on each side at the rear of the rack. All of the internal components  receive their power from these intelligent PDUs. The PDUs are cabled for redundancy. GLYPH<SM590000> A newly designed vertical cable management guide (“spine”) can assist with proper cable  management for fiber, copper, and coupling cables. The spine is shipped with  configurations that contain three or four PCIe+ I/O drawers or with the 16U Reserved  feature (FC 0617). All external cabling to the system (from top or bottom) can use the  spine to minimize interference with the PDUs mounted on the sides of the rack.  GLYPH<SM590000> The z14 ZR1 server (as its predecessor, the z13s) has the option of ordering the  infrastructure to support the top and bottom exit of fiber optic and copper cables. The rack with the spine mounted is shown in Figure 2-2. It and includes removable hooks  that can be placed in appropriate slots throughout the length of the spine. Figure 2-2 Cable management spine 2.1.1 z14 ZR1 configurations All system components are designed and integrated in an IBM 19-inch frame (rack)$^{2}$. The  possible configurations of the system (rear view) are shown in Figure 2-3 on page 24.  Consider the following points: GLYPH<SM590000> The z14 ZR1 system is built in a 42 EIA units rack (A-frame). The base rack is 40 EIA units  high with a 2U removable top. FC 9975 is available if a height reduction is necessary. 2 The components cannot be installed in a customer supplied rack. The term “frame” can also be used  interchangeably with “rack”. Chapter 2. Central processor complex hardware components  23