HDH(4)                 OpenBSD Programmer's Manual (VAX)                HDH(4)

NAME
     hdh - ACC IF-11/HDH IMP interface

SYNOPSIS
     pseudo-device imp
     device hdh0 at uba0 csr 166740 vector hdhintr

DESCRIPTION
     The hdh device provides an HDLC Host (HDH) interface to an IMP. It is
     normally used when participating in the DARPA Internet.  The controller
     itself is not accessible to users, but instead provides the hardware sup-
     port to the IMP interface described in imp(4). The configuration entry
     for the IMP must also include the pseudo-device as shown above in the
     SYNOPSIS.

DIAGNOSTICS
     hdh%d: not alive.  The initialization routine was entered even though the
     device did not autoconfigure.  This indicates a system problem.

     hdh%d: cannot get chan %d uba resources.  Insufficient UNIBUS resources
     existed to initialize the device.  This is likely to be a shortage of
     UNIBUS mapping registers.

     hdh%d: LINE UP.  This indicates that both the HDLC and HDH protocols have
     declared the link to the IMP alive.

     hdh%d: LINE DOWN.  This indicates that the link to the IMP has died.

     hdh%d: TIMEOUT.
     hdh%d: HOST DATA ERROR.
     hdh%d: IMP SEQUENCE ERROR.
     hdh%d: HOST SEQUENCE ERROR.  These errors indicate that an HDH protocol
     error has been detected.

     hdh%d: cannot get supervisor cmnd buffer.  This error indicates that an
     mbuf could not be allocated to send a command to the IF-11/HDH.

     Any other error message from hdh%d: indicates a serious error detected by
     either the driver or the IF-11/HDH firmware.

SEE ALSO
     netintro(4)

HISTORY
     The hdh driver appeared in 4.3BSD.

OpenBSD 3.0                     March 27, 1991                               1
