DZ(4) Kernel Interfaces Manual DZ(4)
NAME
dz - DZ-11 communications multiplexer
SYNOPSIS
/sys/conf/SYSTEM:
NDZ dz_units # DZ11; NDZ is in units of boards (8 each)
/etc/dtab:
#Name Unit# Addr Vector Br Handler(s) # Comments
dz ? 160100 310 5 dzrint dzdma # dz11 terminal mux
major device number:
raw: 2
minor device encoding:
bits 0007 specify line on DZ unit
bits 0170 specify DZ unit
bit 0200 specifies non-blocking open (``CD always on'')
DESCRIPTION
A DZ11 provides 8 communication lines with partial modem control, adequate for UNIX dialup use. Each line attached to the DZ11 communica-
tions 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.
FILES
/dev/tty[0-9][0-9]
/dev/ttyd[0-9a-f] dialups
/dev/MAKEDEV script to create special files
/dev/MAKEDEV.local script to localize special files
SEE ALSO
tty(4), dtab(5), autoconfig(8)
DIAGNOSTICS
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 serious.
3rd Berkeley Distribution January 28, 1988 DZ(4)