Server hardware manuals

In general:
The spec sheet is two pages and has high-level hardware information.
The owner's manual is long (>100 pages), and has detailed hardware configuration, maintenance, and troubleshooting information.
The technical guide is shorter than the owner's manual and enumerates any possible hardware configurations.

Dell PowerEdge 6950

• Dell Support
• Spec Sheet
• Owner's Manual
• Getting Started Guide

Dell PowerEdge R410

• Dell Support
• Spec Sheet
• Owner's Manual
• Technical Guide

Dell PowerEdge R520

• Dell Support
• Owner's Manual
• Technical Guide

Dell PowerEdge R720

• Dell Support
• Spec Sheet
• Owner's Manual
• Technical Guide

Other

• Dell PowerEdge Rail Systems