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DZ(4) Device Drivers Manual (vax) DZ(4)

dzDZ-11 multiplexer device interface

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

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 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.

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.


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.

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

A dz driver appeared in Version 7 AT&T UNIX/32V.

August 18, 2008 OpenBSD-5.3