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intro(7)           FreeBSD Miscellaneous Information Manual           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
       following 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
                 special 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
                 interface 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
                 compatibility), 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
       interface card instance 0, target address 6, and unit 0.  Absence of
       indicates 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
       connected 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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