hdh.4

早期freebsd实现

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.\"     @(#)hdh.4	8.1 (Berkeley) 6/5/93
.\"
.Dd June 5, 1993
.Dt HDH 4 vax
.Os BSD 4.3
.Sh NAME
.Nm hdh
.Nd
.Tn ACC
.Tn IF-11/HDH 
.Tn IMP
interface
.Sh SYNOPSIS
.Cd "pseudo-device imp"
.Cd "device hdh0 at uba0 csr 166740 vector hdhintr"
.Sh DESCRIPTION
The 
.Nm hdh
device provides an
.Tn HDLC
Host
.Pq Tn HDH
interface to an
.Tn IMP .
It is normally used when participating
in the
.Tn DARPA
Internet.  The controller itself is not accessible
to users, but instead provides the hardware support to the
.Tn IMP
interface described in
.Xr imp 4 .
The configuration entry for the
.Tn IMP
must also include the
.Em pseudo-device
as shown above in the
.Sx SYNOPSIS .
.Sh DIAGNOSTICS
.Bl -diag
.It hdh%d: not alive.
The initialization routine was entered even though the device
did not autoconfigure.  This indicates a system problem.
.Pp
.It hdh%d: cannot get chan %d uba resources.
Insufficient
.Tn UNIBUS
resources existed to initialize the device.
This is likely to be a shortage of
.Tn UNIBUS
mapping registers.
.Pp
.It hdh%d: LINE UP.
This indicates that both the
.Tn HDLC
and
.Tn HDH
protocols have declared the
link to the
.Tn IMP
alive.
.Pp
.It hdh%d: LINE DOWN.
This indicates that the link to the
.Tn IMP
has died.
.Pp
.It hdh%d: TIMEOUT.
.It hdh%d: HOST DATA ERROR.
.It hdh%d: IMP SEQUENCE ERROR.
.It hdh%d: HOST SEQUENCE ERROR.
These errors indicate that an
.Tn HDH
protocol error has been detected.
.Pp
.It hdh%d: cannot get supervisor cmnd buffer.
This error indicates that an
.Em mbuf
could not be allocated to send a command to the
.Tn IF-11/HDH .
.El
.Pp
Any other error message from hdh%d: indicates a serious error
detected by either the driver or the
.Tn IF-11/HDH
firmware.
.Sh SEE ALSO
.Xr netintro 4
.Sh HISTORY
The
.Nm
driver appeared in
.Bx 4.3 .