SYSTEM

It depends on the fact that powerbooks are able to cycle down their CPU speed, which as far as I know only power books can do.

'Gestalt FN from ArielMars@aol.com

LOCAL MODE
DIM selector&, gestaltResponse&
LOCAL FN scrollGestaltFN(selector&, gestaltResponse&)
  `  subq.l #2,sp
  ` move.l  ^selector&,-(sp)
  ` move.l  ^gestaltResponse&,-(sp)
  MACHLG &225F
  MACHLG &201F
  MACHLG &A1AD
  MACHLG &2288
  MACHLG &3E80
  ` move.w  (sp)+,D0
  ` ext.l   D0
END FN

isPowerBook% = _false
DIM gestaltResponse&
LONG IF FN scrollGestaltFN(_Gestaltpowermgrattr, @gestaltResponse&) = _noErr
  LONG IF (gestaltResponse& AND _GestaltPmgrExists) = _false
    REM Power manager Exists
    LONG IF (gestaltResponse& AND _GestaltPmgrCPUidle)  REM The CPU can idle
        isPowerBook% = _true
    END IF
  END IF
END IF