INTRO(4)            UNIX Programmer's Manual             INTRO(4)



NAME
     intro - introduction to special files

HP-UX COMPATIBILITY
     Remarks:  In general, device drivers are not portable across
               systems;  however,  every  effort has been made to
               make their behavior portable.  Due to variation in
               hardware,  this  is not always possible.  Programs
               which use these drivers  directly  are  at  higher
               than average risk of not being portable.

DESCRIPTION
     This section describes various special files that  refer  to
     specific  HP  peripherals  and device drivers.  The names of
     the entries are generally derived from the  type  of  device
     being  described (disc, plotter, etc.), not the names of the
     special  files  themselves.   Characteristics  of  both  the
     hardware  device  and  the corresponding HP-UX device driver
     are discussed where applicable.

     The devices are divided into two catagories,  unblocked  and
     blocked. An unblocked device is also called a raw or a char-
     acter mode device.  An unblocked  device,  such  as  a  line
     printer, uses a character special file.

     Blocked devices, as the  name  implies,  transfers  data  in
     blocks  via  the  systems normal buffering mechanism.  Block
     devices use block special files.

     For specific details about the default special files shipped
     with  your  system,  consult the System Administrator Manual
     for your system.

     You associate the name you want with a specific device  when
     you create a special file for that device using the _m_k_d_e_v(8)
     and _m_k_n_o_d(8) commands.   When  creating  additional  special
     files,  it  is recommended that the following naming conven-
     tion be followed:

     [ r ] dev_id [ prod_no ] [ model_initial ] [ s|d|i ] [ . ] [
     digit ]

     where:

     r          indicates that the device is  treated  as  a  raw
                device;









Printed 12/17/84                                                1






INTRO(4)            UNIX Programmer's Manual             INTRO(4)



     dev_id     consists of one of the following mnemonics:















     prod_no    is the HP product number for the device;

     model_initial
                is the initial (if any) associated with the  pro-
                duct number for the device;

     s|d|i      used with the HP  9895A;  specifies  whether  the
                media  is  single-sided (s), double-sided (d), or
                in IBM format;

     .digit     used when more than one identical device is  con-
                nected  to  the  system;  for  example, if two HP
                2631G printers are connected, their special  file
                names  would  be  lp2631g and lp2631g.1.  Or, you
                might name them lp and lp.1.  You create and name
                special files with the _m_k_n_o_d(8) and _m_k_d_e_v(8) com-
                mands.

HARDWARE DEPENDENCIES
     Series 500/600/700:
          You cannot open a block special  file  for  reading  or
          writing.

          The IBM format is not supported for the HP 9895A.















Printed 12/17/84                                                2