HP Certified: HP-UX System Administration

All devices in an HP-UX system are represented by one or more device files. I/O operations on these devices are carried out using these files. The device files are present under the /dev directory. Every device file is linked to a device with a particular hardware path. Hardware paths show the physical location of the device inside the system. A hardware path starts with a bus number and contains a bus converter number and the instance number of the interface card. A major device number shows the device driver, and a minor device number identifies the device's hardware address and, optionally , other device characteristics. Character or raw devices are used for transferring one character of data at one time, while block devices are used for transferring a block of data at one time. All SCSI device files follow a general naming convention c#t#d# , where the first # sign shows the instance number of an interface card, the second is for the SCSI target address, and the third is for LUN. Tape device files have additional characters that show the characteristics of the tape drive. Device files can be listed with the help of the ls , ioscan , and lssf commands. New device files are created with one of the following methods .

• autoconfiguration

• using the insf command

• using the mksf command

• using the mknod command

• using SAM

Terminal device files are in the /dev directory and show to which MUX port a terminal is connected. Pseudoterminal device files are used for making network connections. Each modem is represented by three device files.