dz(4) [bsd man page]
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)
Check Out this Related Man Page
DHU(4) Kernel Interfaces Manual DHU(4) NAME
dhu - DHU-11 communications multiplexer SYNOPSIS
/sys/conf/SYSTEM: NDHU dhu_units # DHU11 /etc/dtab: #Name Unit# Addr Vector Br Handler(s) # Comments du ? 160020 310 5 dhurint dhuxint # dhu11 terminal mux major device number(s): raw: 4 minor device encoding: bits 0017 specify line on DHU unit bits 0060 specify DHU unit bit 0100 specify RTS/CTS flow control bit 0200 specifies non-blocking open (``CD always on'') DESCRIPTION
A DHU-11 provides 16 communication lines. Each line attached to the DHU-11 communications multiplexer behaves as described in tty(4). Input and output for each line may indepen- dently be set to run at any of 13 speeds (50, 200 and 38400 baud are not available); see tty(4) for the encoding. Bit 0200 of the minor device number for DHU 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 "4, 130" via mknod /dev/ttyS2 c 4 130 would cause line ttyS2 to be treated in this way. Turning on bit 6 (adding 64) to the minor device number via mknod /dev/ttyS2 c 4 194 enables RTS/CTS flow control. The DHU-11 driver normally uses input silos and delays receiver interrupts by 20 milliseconds rather than taking an interrupt on each input character. FILES
/dev/tty[S-Z][0-9a-f] SEE ALSO
tty(4) DIAGNOSTICS
dhu(%d,%d) NXM. No response from UNIBUS on a DMA transfer within a timeout period. This has never been observed on a PDP-11 and is believed to be a carryover from the VAX driver when it was ported. It is not serious. dhu%d %d overruns. The character input silo overflowed before it could be serviced. This message is printed only at line close time rather than on each overrun error. Kernel printf's are not interrupt driven and caused more overruns by blocking interrupts for lengthy periods of time. NOTES
The driver currently does not make full use of the hardware capabilities of the DHU-11, for dealing with XON/XOFF flow-control or hard- wired lines for example. The 4 40-way cables are a pain. 3rd Berkeley Distribution May 31, 1997 DHU(4)