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

NAME
     dmz - DMZ-32 terminal multiplexor

SYNOPSIS
     device dmz0 at uba? csr 0160540 vector dmzrinta dmzxinta dmzrintb
           dmzxintb dmzrintc dmzxintc

DESCRIPTION
     The dmz device provides 24 lines of asynchronous serial line support.
     Modem control on all ports is available as an option for the H3014 dis-
     tribution panel.

     An optional argument flags may be supplied with the device specification
     for dmz in the config file indicating that the line corresponding to bit
     number i is not properly connected, and should be treated as hard-wired
     with carrier always present.  Thus specifying `flags 0x000004' for dmz0
     would cause line ttya2 to be treated in this way.

     Normal I/O control parameters for individual lines are managed by
     ioctl(2) calls.  Line speeds (there are 16 choices for the DMZ) may be
     initiated via getty(8) and stty(1) or may be communicated by other pro-
     grams which utilize ioctl(2) such as ifconfig(8), see tty(4).

     The dmz driver normally enables the input silos with a short timeout (30
     milliseconds); this allows multiple characters to be received per inter-
     rupt during periods of high-speed input.

FILES
     /dev/tty[abcefg][0-9a-n]

DIAGNOSTICS
     dmz%d: NXM line %d.  No response from the UNIBUS on a DMA transfer within
     a timeout period.  This is often followed by a UNIBUS adapter error.
     This occurs most frequently when the UNIBUS is heavily loaded and when
     devices which hog the bus (such as RK07s) are present.  It is not seri-
     ous.

     dmz%d: silo overflow.  The character input silo overflowed before it
     could be serviced.  This can happen if a hard error occurs when the CPU
     is running with elevated priority, as the system will then print a mes-
     sage on the console with interrupts disabled.  It is not serious.

SEE ALSO
     tty(4)

HISTORY
     The dmz driver appeared in 4.3BSD.

BUGS
     It should be possible to set the silo timeout with a configuration file
     option, as the value is a trade-off between efficiency and response time
     for flow control and character echo.

OpenBSD 3.0                     March 27, 1991                               1
