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intro(7)	       Miscellaneous Information Manual		      intro(7)

NAME
       intro - introduction to device special files

DESCRIPTION
       This  section  describes	the device special files used to access	HP pe-
       ripherals 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 de-
       vice 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  in-
		 terface
			   card.   There  is no	direct correlation between in-
			   stance 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
		 LUN).

       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.

EXAMPLES
       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  ad-
       dress  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  de-
       tails).

WARNINGS
       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.

SEE ALSO
       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

								      intro(7)

NAME | DESCRIPTION | EXAMPLES | WARNINGS | SEE ALSO

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