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intro(7)							      intro(7)

       intro - introduction to device special files

       This  section  describes	 the  device  special  files used to access HP
       peripherals and device drivers.	The names of the entries are generally
       derived from the	type of	device being described (disk, terminal,	etc.),
       not the names of	the device special files or device drivers themselves.
       Characteristics of both the hardware device and the corresponding HP-UX
       device driver are discussed where applicable.

       The devices can be classified in	two categories,	raw and	block.	A  raw
       or  character-mode device, such as a line printer, transfers data in an
       unbuffered stream and uses a character device special file.

       Block devices, as the name implies, transfer data in blocks by means of
       the  system's  normal  buffering	 mechanism.   Block  devices use block
       device special files and	may have a character device interface too.

       A device	special	file name becomes associated with a  device  when  the
       file  is	 created, using	the mksf(1M), insf(1M),	or mknod(1M) commands.
       When creating device special files, it is recommended that the  follow-
       ing standard naming convention be used:

       prefix	 indicates the subdirectory for	the device class (for example,
		 for raw device	special	files for disks, for block device spe-
		 cial files for	disks, for raw tape devices).

       devspec	 indicates  hardware  path information and is typically	in the
		 format	as follows:

		 Instance number assigned  by  the  operating  system  to  the
			   card.   There  is  no  direct  correlation  between
			   instance number and physical	slot number.

		 Target	address	on a remote bus	(for example, SCSI address).

		 Device	 unit  number at the target address (for example, SCSI

       options	 Further  qualifiers,  such as disk section (for backward com-
		 patibility), tape density selection for  a  tape  device,  or
		 surface specification for magneto-optical media.

       Hardware	path information can be	derived	from ioscan(1M)	output.

       The following is	an example of a	disk device special file name:

       where  indicates	 block disk access and indicates disk access at	inter-
       face card instance 0, target address 6, and unit	0.  Absence  of	 indi-
       cates access to the entire disk (see disk(7) for	details).

       The following is	an example of a	tape device special file name:

       where  indicates	 raw  magnetic tape, indicates that the	device is con-
       nected to interface card	 instance  2,  indicates  that	target	device
       address	is set to 3, indicates that the	tape transport resides at unit
       address 0, and identifies the tape format  as  QIC150  (see  mt(7)  for

       In the past, other naming conventions have been used for	device special
       files.  Using ln(1) to create a link between the	old and	 new  standard
       name is useful as a temporary expedient until all programs using	an old
       naming convention have been converted.

       ioscan(1M), mksf(1M), insf(1M), lssf(1M), hier(5), introduction(9).

       The system administrator	manual for your	system.

       Web access to HP-UX documentation at



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