DZ(4)                  OpenBSD Programmer's Manual (VAX)                 DZ(4)

NAME
     dz - DZ-11 multiplexer device interface

SYNOPSIS
     dz0 at uba0 csr 0160100
     dz0 at vsbus0 csr 0x200a0000 (DC-367)
     dz0 at vsbus0 csr 0x25000000 (VS4000/90 4000/10x MV3100/9x)
     dz* at fwio?                 (VAXstation 35x0 and 38x0)
     lkkbd0 at dz0 line 0
     lkms0  at dz0 line 1

DESCRIPTION
     A DZ-11 provides 4 or 8 communication lines with partial modem control,
     adequate for OpenBSD dialup use.

     Normal I/O control parameters for individual lines are managed by
     ioctl(2) calls.  Line speeds may be initiated via the ttys(5) file or
     stty(1), see tty(4).

     The dz driver monitors the rate of input on each board, and switches be-
     tween 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.

     On VAXstation systems, lines 0 and 1 are tied to the keyboard and mouse
     connectors, which are driven by the lkkbd and lkms drivers, respectively.

FILES
     /dev/tty0[0-7]  dialups

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 mes-
     sage on the console with interrupts disabled.  It is not serious.

SEE ALSO
     intro(4), lkkbd(4), lkms(4), tty(4), uba(4), vsbus(4)

HISTORY
     A dz driver appeared in Version 32V AT&T UNIX.

OpenBSD 4.7                     August 18, 2008                              1
