8.1 Device OverviewThe PC I/O ArchitectureThe Structure of the FreeBSD Mass Storage I/O SubsystemDevice Naming and Access8.2 I/O Mapping from User to DeviceDevice DriversI/O QueueingInterrupt Handling8.3 Character DevicesRaw Devices and Physical I/OCharacter-Oriented DevicesEntry Points for Character Device Drivers8.4 Disk DevicesEntry Points for Disk Device DriversSorting of Disk I/O RequestsDisk Labels8.5 Network DevicesEntry Points for Network DriversConfiguration and ControlPacket ReceptionPacket Transmission8.6 Terminal HandlingTerminal-Processing ModesUser InterfaceProcess Groups, Sessions, and Terminal ControlTerminal OperationsTerminal Output (Upper Half)Terminal Output (Lower Half)Terminal InputClosing of Terminal Devices8.7 The GEOM LayerTerminology and Topology RulesChanging TopologyOperationTopological Flexibility8.8 The CAM LayerThe Path of a SCSI I/O Request Through the CAM SubsystemATA Disks8.9 Device ConfigurationDevice IdentificationAutoconfiguration Data StructuresResource Management8.10 Device VirtualizationInteraction with the HypervisorVirtioXenDevice Pass-ThroughExercisesReferences