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 usually 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 character-mode device.  An unblocked device, such as a line printer, uses a character special file. 

Blocked devices, as the name implies, transfer data in blocks via the system’s 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. 

The desired name is associated with a specific device when mknod(1M) is used to create a special file for that device. The following naming convention is recommended for use when creating special files (special file names are are independent of the hardware):

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

where:

r if present, indicates that the device is treated as a raw device; otherwise, the file is a block-mode file. 

dev_id consists of one of the following mnemonics:

ctCS/80 catridge tape drive
hdhard disc
mt9-track tape drive
fdflexible disc
lpline printer
digdigitizer
pltplotter or graphics CRT display

prod_no HP product number for the device;

model_initial the letter suffix (if any) associated with the device model number;

s|d|i used with the HP 9895A to specify Single-sided, Double-sided, or IBM media format;

 .digit used when two or more identical devices are connected to the system; for example, if two HP 2631G printers are connected to the system, their special file names would be lp2631g and lp2631g.1 (they could also be named lp and lp.1). 

HARDWARE DEPENDENCIES

Series 500:
Block special files cannot be opened for reading or writing.
The IBM format capability in the HP 9895A is not officially supported on HP-UX. 

Hewlett-Packard  —  last mod. May 11, 2021