IBM 704 - Manual (Page 26)

Status Indicators
The most commonly used status indicators on the front of the server
appear in the following illustration.
Diskette In-Use
Light
Power On Light
Power Failure Light
Cooling Failure Light
Drive Failure Light
Information Panel
Hard Disk
Power-On
Hard Disk
In-Use
Hard Disk
Fault
CD-ROM
In-Use
Light
8 PC Server 704 User's Handbook