BSD 2.11 - man page for dz (bsd section 4)
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dz - DZ-11 communications multiplexer
NDZ dz_units # DZ11; NDZ is in units of boards (8 each)
#Name Unit# Addr Vector Br Handler(s) # Comments
dz ? 160100 310 5 dzrint dzdma # dz11 terminal mux
major device number:
minor device encoding:
bits 0007 specify line on DZ unit
bits 0170 specify DZ unit
bit 0200 specifies non-blocking open (``CD always on'')
A DZ11 provides 8 communication lines with partial modem control, adequate for UNIX dialup
use. Each line attached to the DZ11 communications multiplexer behaves as described in
tty(4) and may be set to run at any of 16 speeds; see tty(4) for the encoding.
Bit 0200 of the minor device number for DZ lines may be set to say that a line is not
properly connected, and that the line should be treated as hard-wired with carrier always
present. Thus creating the special character device node "2, 130" via mknod /dev/tty02 c
2 130 would cause line tty02 to be treated in this way.
The dz driver monitors the rate of input on each board, and switches between the use of
character-at-a-time interrupts and input silos. While the silo is enabled during periods
of high-speed input, the driver polls for input 30 times per second.
/dev/MAKEDEV script to create special files
/dev/MAKEDEV.local script to localize special files
tty(4), dtab(5), autoconfig(8)
dz%d: silo overflow. The 64 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
3rd Berkeley Distribution January 28, 1988 DZ(4)
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