NAME
dmz —
DMZ-32 serial terminal
multiplexor
SYNOPSIS
dmz0 at uba? csr 0160540 vector dmzrinta dmzxinta dmzrintb
dmzxintb dmzrintc dmzxintc
DESCRIPTION
NOTE: This driver has not been ported from
4.4BSD yet.
The
dmz device provides 24 lines of asynchronous serial line
support. Modem control on all ports is available as an option for the H3014
distribution 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 programs which use
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
interrupt 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 serious.
- 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 message 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.