IBM ServeRAID User Reference page 106

Function What it does
unattended This function enables or disables
unattended mode. This controller setting
determines how the BIOS handles failures
during system startup.
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IBM ServeRAID: User's Reference, Version 5.10
Command and supported operating systems
IPSSEND UNATTENDED controller ON/OFF
where:
v controller is the ServeRAID controller number (1–12)
v ON enables the feature
v OFF disables the feature
Supported operating systems: Windows, NetWare, OS/2,
Linux, OpenServer, UnixWare, Open UNIX, and DOS