fddin Special File

Purpose

Provides access to the FDDI device driver by way of the FDDI device handler.

Description

The fddin special file provides access to the FDDI device handler that provides access to a FDDI local area network.

When accessing the FDDI device driver, the following information should be taken into account.

Driver Initialization and Termination

The device driver can be loaded and unloaded. The device driver supports the configuration calls to initialize and terminate itself.

Special File Support

Subroutine calls other than those made with the open and close subroutines are discussed based on the mode in which the device driver is operating.

Subroutine Support

The FDDI device driver provides specific support for the open, close, read, write, ioctl, select, and poll subroutines.

The device driver supports the /dev/fddin special file as a character-multiplex special file. The special file must be opened for both reading and writing. There are no particular considerations for closing the special file. The special file name used in an open call differs depending upon how the device is to be opened. Types of special file names are:

Item Description
/dev/fddin Starts the device driver for the selected port.
/dev/fddin/D Starts the device driver for the selected port in Diagnostic mode.
/dev/fddin/C Starts the device driver for the selected port in Diagnostic Configuration mode.

Error Codes

The following error conditions may be encountered when accessing the FDDI device driver through the /dev/fddin special file. The error codes can be found in the /usr/include/sys/errno.h file.

Item Description
ENODEV Indicates that an invalid minor number was specified.
EINVAL Indicates that an invalid parameter was specified.
ENOMEM Indicates that the device driver was unable to allocate the required memory.
EINTR Indicates that a system call was interrupted.
EPERM Indicates that the Diagnostic mode open request was denied because the device was already open.
EACCES Indicates one of the following:
  • A non-privileged user tried to open the device in Diagnostic mode.
  • An illegal call from a kernel-mode user.
  • An illegal call from a user-mode user.
ENETDOWN Indicates one of the following:
  • The network is down. The device is unable to process the requested operation.
  • An unrecoverable hardware error.
ENETUNREACH Indicates that the device is in Network Recovery mode and is unable to process the requested operation.
ENOCONNECT Indicates that the device has not been started.
EAGAIN Indicates that the transmit queue is full.
EFAULT Indicates that an invalid address was supplied.
EIO Indicates an error. See the status field for detailed information.
EMSGSIZE Indicates that the data was too large to fit into the receive buffer and that no ext parameter was supplied to provide an alternate means of reporting this error with a status of CIO_BUF_OVFLW.