bk(4) [bsd man page]
BK(4) Kernel Interfaces Manual BK(4) NAME
bk - line discipline for machine-machine communication (obsolete) SYNOPSIS
Not currently supported under 2.11BSD DESCRIPTION
This line discipline provides a replacement for the old and new tty drivers described in tty(4) when high speed output to and especially input from another machine is to be transmitted over a asynchronous communications line. The discipline was designed for use by the Berke- ley network. It may be suitable for uploading of data from microprocessors into the system. If you are going to send data over asynchro- nous communications lines at high speed into the system, you must use this discipline, as the system otherwise may detect high input data rates on terminal lines and disables the lines; in any case the processing of such data when normal terminal mechanisms are involved satu- rates the system. The line discipline is enabled by a sequence: #include <sgtty.h> int ldisc = NETLDISC, fildes; ... ioctl(fildes, TIOCSETD, &ldisc); A typical application program then reads a sequence of lines from the terminal port, checking header and sequencing information on each line and acknowledging receipt of each line to the sender, who then transmits another line of data. Typically several hundred bytes of data and a smaller amount of control information will be received on each handshake. The old standard teletype discipline can be restored by doing: ldisc = OTTYDISC; ioctl(fildes, TIOCSETD, &ldisc); While in networked mode, normal teletype output functions take place. Thus, if an 8 bit output data path is desired, it is necessary to prepare the output line by putting it into RAW mode using ioctl(2). This must be done before changing the discipline with TIOCSETD, as most ioctl(2) calls are disabled while in network line-discipline mode. When in network mode, input processing is very limited to reduce overhead. Currently the input path is only 7 bits wide, with newline the only recognized character, terminating an input record. Each input record must be read and acknowledged before the next input is read as the system refuses to accept any new data when there is a record in the buffer. The buffer is limited in length, but the system guarantees to always be willing to accept input resulting in 512 data characters and then the terminating newline. User level programs should provide sequencing and checksums on the information to guarantee accurate data transfer. SEE ALSO
tty(4) DIAGNOSTICS
None. BUGS
The Purdue uploading line discipline, which provides 8 bits and uses timeout's to terminate uploading should be incorporated into the stan- dard system, as it is much more suitable for microprocessor connections. 4th Berkeley Distribution January 27, 1996 BK(4)
Check Out this Related Man Page
LDATTACH(8) Linux Programmer's Manual LDATTACH(8) NAME
ldattach - attach a line discipline to a serial line SYNOPSIS
ldattach [-dhV78neo12] [-s speed] [-i iflag] ldisc device DESCRIPTION
The ldattach daemon opens the specified device file (which should refer to a serial device) and attaches the line discipline ldisc to it for processing of the sent and/or received data. It then goes into the background keeping the device open so that the line discipline stays loaded. The line discipline ldisc may be specified either by name or by number. In order to detach the line discipline, kill(1) the ldattach process. With no arguments, ldattach prints usage information. LINE DISCIPLINES
Depending on the kernel release, the following line disciplines are supported: TTY(0) The default line discipline, providing transparent operation (raw mode) as well as the habitual terminal line editing capabilities (cooked mode). SLIP(1) Serial Line IP (SLIP) protocol processor for transmitting TCP/IP packets over serial lines. MOUSE(2) Device driver for RS232 connected pointing devices (serial mice). PPP(3) Point to Point Protocol (PPP) processor for transmitting network packets over serial lines. STRIP(4) AX25(5) X25(6) Line driver for transmitting X.25 packets over asynchronous serial lines. 6PACK(7) R3964(9) Driver for Simatic R3964 module. IRDA(11) Linux IrDa (infrared data transmission) driver - see http://irda.sourceforge.net/ HDLC(13) Synchronous HDLC driver. SYNC_PPP(14) Synchronous PPP driver. HCI(15) Bluetooth HCI UART driver. GIGASET_M101(16) Driver for Siemens Gigaset M101 serial DECT adapter. PPS(18) Driver for serial line Pulse Per Second (PPS) source. OPTIONS
-d | --debug Causes ldattach to stay in the foreground so that it can be interrupted or debugged, and to print verbose messages about its progress to the standard error output. -h | --help Prints a usage message and exits. -V | --version Prints the program version. -s value | --speed value Set the speed of the serial line to the specified value. -7 | --sevenbits Sets the character size of the serial line to 7 bits. -8 | --eightbits Sets the character size of the serial line to 8 bits. -n | --noparity Sets the parity of the serial line to none. -e | --evenparity Sets the parity of the serial line to even. -o | --oddparity Sets the parity of the serial line to odd. -1 | --onestopbit Sets the number of stop bits of the serial line to one. -2 | --twostopbits Sets the number of stop bits of the serial line to two. -i value | --iflag [-]value{,...} Sets the specified bits in the c_iflag word of the serial line. Value may be a number or a symbolic name. If value is prefixed by a minus sign, clear the specified bits instead. Several comma separated values may be given in order to set and clear multiple bits. SEE ALSO
inputattach(1), ttys(4) AUTHOR
Tilman Schmidt (tilman@imap.cc) AVAILABILITY
The ldattach command is part of the util-linux package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/. Linux 2.6 14 February 2010 LDATTACH(8)