Block device: a buffered device with a structured random access method. Block devices are typically a disk file system (DISK file system). Character Device: It is also known as a bare device, is a non-buffered continuous, orientation device. Character equipment is usually system peripheral devices such as terminals, printers, and the like. Main device number (Major Number): Identify the device driver in the system kernel. MINOR NUMBER: Identifies a special device type. The ODM database consists of a predefined database and a custom database (CUSTOMIZED DATABASE). Information and properties of all logical devices in the system are used. Among them: Predefined Database: Contains all system-configured systems supported device (supported devices) configured data. Customized Database: Contains all defined defined devices and available (Available Devices) device configuration data.
Class of the device: Identifying the subclass of the device: Identify how the device is connected to the type of system device (TYPE): Identifies the name of the device's type of device (Name): Identifies the logic device name # lsdev [ -C | -p | -h] -c device_class device list-C: Specifies to find information from the ODM custom database (Customized Database) - P: Specifies to find information from the ODM's predefined database (PREDIFINED DATABASE) --H: In the output, the title-C: Displays device information that belongs to the specified device class (Class), as: display all supported devices in the system: # lsdev -ph Displays all definitions in the current system and available Equipment (AVAILABLE) Information: # lsdev-ch # lsattr -e -l logical_device_name device Properties list-E: Display Specified Device Valid Properties -L: Displays the device properties of the specified logic device name (Name) # chdev -l logical_device_name - a attribute = value Change device properties such as: Change system kernel device parameters: # chdev -l sys0 -a maxuProc = 100 Change the maximum process number of the system to 100 #lsattr -d -l sys0 -a maxuProc display system maximum process number # lscfg -v [-l logical_device_name] Displays the configuration information of the device in the current system -V: Display detailed device configuration information -L logical_device_name: Display the configuration command for the device configuration information device for the specified device: # mkdev -c class -s Subclass -t type -p parent_adapter -w connection_location -a attribute = value -c class: Specifies the class to which the device belongs (such as: tape): Specifies the subclass of the device (eg SCSI) -t type: specified device belong Type (such as: 150MB) -P parent_adapter: Specify the parent card number of the device (such as: SCSI0) --W connection_location: Specify the location or address of the device to the parent card (eg 5, 0) -a attribute = value: Specify The properties of the device (such as: Ret = no) device State: undefined: There is no presence record of this device in the system (the device information is stored in a predefined database) (Support) Defined: The system has assigned a logical device name and port for this device, but the system does not access this device (device information Stored in the custom database) AVAILABLE: The device has defined in the system and can be used (device information is stored in custom database)
