DZ(4) BSD/vax Kernel Interfaces Manual DZ(4)NAMEdz — DZ-11 multiplexer device interface
device dz0 at uba0 csr 0160100 vector dzrint dzxint
A DZ-11 provides 8 communication lines with partial modem control, ade‐
quate for UNIX dialup use.
An optional argument flags may be supplied with the device specification
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 car‐
rier always present. Thus specifying ‘flags 0x04’ for dz0 would cause
line tty02 to be treated in this way.
Normal I/O control parameters for individual lines are managed by
ioctl(2) calls. Line speeds may be initiated via the ttys(5) file,
stty(1) or ifconfig(8) to name a few, see tty(4).
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.
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 mes‐
sage on the console with interrupts disabled. It is not serious.
SEE ALSOstty(1), tty(4), ttys(5), getty(8)HISTORY
A dz driver appeared in Version 32V AT&T UNIX.
4th Berkeley Distribution June 5, 1993 4th Berkeley Distribution