dmz(4) - NetBSD Manual Pages

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DMZ(4)                NetBSD/vax Kernel Interfaces Manual               DMZ(4)

dmz -- DMZ-32 serial terminal multiplexor
dmz0 at uba? csr 0160540 vector dmzrinta dmzxinta dmzrintb dmzxintb dmzrintc dmzxintc
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 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 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 inter- rupt during periods of high-speed input.
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.
The dmz driver appeared in 4.3BSD.
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. NetBSD 9.0 June 5, 1993 NetBSD 9.0
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