IBM i series Handbook page 380

Internal Magnetic Media
#6425 Optional CD-ROM Feature
Available on Models 720, 620, and S20, or in the #7130 Expansion cage on the #5064/#9364
System Expansion Unit with a #9329/#9330 PCI Integrated Expansion Unit.
Prerequisites: The #2726/#2740/#2741/#2748 PCI RAID Disk Unit Controller and the #9728
Base PCI RAID Disk Unit Controller.
Not supported together with #9331 Expansion Unit for SPD cards in the #5064/#9364 System
Expansion Unit.
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iSeries Handbook