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 support to the IMP interface described in imp(4). When configuring, the imp pseudo-device must also be included.

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: HOST SEQUENCE ERROR
hdh%d: IMP SEQUENCE ERROR
hdh%d: HOST DATA ERROR
hdh%d: TIMEOUT
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)