+.TP
+.B darwin
+Access method used on Mac OS X / Darwin. Must be run as root and the system
+must have been booted with debug=0x144.
+.TP
+.B win32-cfgmgr32
+Device listing on Windows systems using the Windows Configuration Manager
+via cfgmgr32.dll system library. This method does not require any special
+Administrator rights or privileges. Configuration Manager provides only basic
+information about devices, assigned resources and device tree structure. There
+is no access to the PCI configuration space but libpci provides read-only
+virtual emulation based on information from Configuration Manager. Starting
+with Windows 8 (NT 6.2) it is not possible to retrieve resources from 32-bit
+application or library on 64-bit system.
+.TP
+.B win32-sysdbg
+Access to the PCI configuration space via NT SysDbg interface on Windows
+systems. Process needs to have Debug privilege, which local Administrators
+have by default. Not available on 64-bit systems and neither on recent 32-bit
+systems. Only devices from the first domain are accessible and only first
+256 bytes of the PCI configuration space is accessible via this method.