User`s guide

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B: Installing Silicon Graphics Prism Modules Into a Rack
Determining Where to Attach the Slide Rail in the Rack
The module requires two units (2U) of space within the rack (one unit is equivalent to 1.75 inches
[44.5 cm]). To determine where you should install the slide rails in the rack, you must count
mounting holes. Each U contains three mounting holes; therefore, in the 2U of space that the
module occupies, there are six mounting holes. The bottom hole of the 2U space is hole 1. The top
mounting hole in the 2U space is hole 6. See Figure B-4.
Note: A module in the rack is identified by the lowest U number that it occupies. For example,
in Figure B-4 the module resides in U5 (the fifth unit within the rack).
Figure B-4 Mounting-hole Pattern of Rack Vertical Rails
To determine how many mounting holes you must count, use the following formula:
3 x (the lowest U number that the module will occupy) - 2.
For example, when you want to install the module in locations U9 and U10, count 25 mounting
holes (3 x 9 - 2) starting from the bottom of the rack. The 25th hole is the first mounting hole of U9.
3
2
1
4
5
6
7
8
3
2
1
4
5
6
7
8
2nd hole
5th hole
2U
1st hole
6th hole
2U
2
TM