Return to dh.4 CVS log

Up to [CSRG BSD Unix] / 43BSDReno / share / man / man4 / man4.vax

Annotation of 43BSDReno/share/man/man4/man4.vax/dh.4, revision 1.1.1.1

1.1       root        1: .\" Copyright (c) 1980 Regents of the University of California.
                      2: .\" All rights reserved.  The Berkeley software License Agreement
                      3: .\" specifies the terms and conditions for redistribution.
                      4: .\"
                      5: .\"    @(#)dh.4        6.2 (Berkeley) 5/16/86
                      6: .\"
                      7: .TH DH 4 "May 16, 1986"
                      8: .UC 4
                      9: .SH NAME
                     10: dh \- DH-11/DM-11 communications multiplexer
                     11: .SH SYNOPSIS
                     12: .B "device dh0 at uba0 csr 0160020 vector dhrint dhxint"
                     13: .br
                     14: .B "device dm0 at uba0 csr 0170500 vector dmintr"
                     15: .SH DESCRIPTION
                     16: A dh-11 provides 16 communication lines; dm-11's may be optionally
                     17: paired with dh-11's to provide modem control for the lines.
                     18: .PP
                     19: Each line attached to the DH-11 communications multiplexer
                     20: behaves as described in
                     21: .IR tty (4).
                     22: Input and output for each line may independently
                     23: be set to run at any of 16 speeds;
                     24: see
                     25: .IR tty (4)
                     26: for the encoding.
                     27: .PP
                     28: Bit
                     29: .I i
                     30: of flags may be specified for a dh to say that a line is not properly
                     31: connected, and that the line should be treated as hard-wired with carrier
                     32: always present.  Thus specifying ``flags 0x0004'' in the specification of dh0
                     33: would cause line ttyh2 to be treated in this way.
                     34: .PP
                     35: The
                     36: .I dh
                     37: driver monitors the rate of input on each board,
                     38: and switches between the use of character-at-a-time interrupts
                     39: and input silos.
                     40: While the silo is enabled during periods of high-speed input,
                     41: the driver polls for input 30 times per second.
                     42: .SH FILES
                     43: /dev/tty[h-o][0-9a-f]
                     44: .br
                     45: /dev/ttyd[0-9a-f]
                     46: .SH "SEE ALSO"
                     47: tty(4)
                     48: .SH DIAGNOSTICS
                     49: \fBdh%d: NXM\fR.  No response from UNIBUS on a dma transfer
                     50: within a timeout period.  This is often followed by a UNIBUS adapter
                     51: error.  This occurs most frequently when the UNIBUS is heavily loaded
                     52: and when devices which hog the bus (such as rk07's) are present.
                     53: It is not serious.
                     54: .PP
                     55: \fBdh%d: silo overflow\fR.  The character input silo overflowed
                     56: before it could be serviced.  This can happen if a hard error occurs
                     57: when the CPU is running with elevated priority, as the system will
                     58: then print a message on the console with interrupts disabled.
                     59: It is not serious.

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.