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Annotation of 43BSDReno/share/doc/smm/13.kchanges/sys.tty.t, revision 1.1

1.1     ! root        1: .\" Copyright (c) 1986 Regents of the University of California.
        !             2: .\" All rights reserved.  The Berkeley software License Agreement
        !             3: .\" specifies the terms and conditions for redistribution.
        !             4: .\"
        !             5: .\"    @(#)sys.tty.t   1.7 (Berkeley) 4/11/86
        !             6: .\"
        !             7: .NH 2
        !             8: Changes in the terminal line disciplines
        !             9: .XP tty.c
        !            10: The kernel maintains the terminal or window size in the tty structure
        !            11: and provides \fIioctl\fP\^s to set and get these values.
        !            12: The window size is cleared on final close.
        !            13: The sizes include rows and columns in characters
        !            14: and may include X and Y dimensions in pixels where that is meaningful.
        !            15: The kernel makes no use of these values, but they are stored here
        !            16: to provide a consistent way to determine the current size.
        !            17: When a new value is set, a SIGWINCH signal is sent to the process group
        !            18: associated with the terminal.
        !            19: .XP
        !            20: The notions of line discipline exit and final close have been separated.
        !            21: \fITtyclose\fP is used only at final close, while \fIttylclose\fP
        !            22: is provided for closing down a discipline.
        !            23: Modem control transitions are handled more cleanly
        !            24: by moving the common code from the terminal hardware drivers
        !            25: into the line disciplines; the \fIl_modem\fP entry in the \fIlinesw\fP
        !            26: is now used for this purpose.
        !            27: \fITtymodem\fP handles carrier transitions for the standard disciplines;
        !            28: \fInullmodem\fP is provided for disciplines with minimal requirements.
        !            29: .XP
        !            30: A new mode, LPASS8, was added to support 8-bit input in normal modes;
        !            31: it is the input analog of LLITOUT.
        !            32: An entry point, \fIcheckoutq\fP, has been added to enable internal
        !            33: output operations (\fIuprintf\fP, \fItprintf\fP) to check for output overflow
        !            34: and optionally to block to wait for space.
        !            35: Certain operations are handled more carefully than before:
        !            36: the use of the TIOCSTI \fIioctl\fP requires read permission on the terminal,
        !            37: and SPGRP is disallowed if the group corresponds with another user's
        !            38: process.
        !            39: \fITtread\fP and \fIttwrite\fP both check for carrier drop when
        !            40: restarting after a sleep.
        !            41: An off-by-one consistency check of \fIuio_iovcnt\fP
        !            42: in \fIttwrite\fP was corrected.
        !            43: A bug was fixed that caused data to be flushed
        !            44: when opening a terminal that was already open when using the ``old''
        !            45: line discipline.
        !            46: \fISelect\fP now returns true for reading if carrier has been lost.
        !            47: While changing line disciplines, interrupts must be disabled until
        !            48: the change is complete or is backed out.
        !            49: If changing to the same discipline, the close and reopen (and probable
        !            50: data flush) are avoided.
        !            51: The \fIt_delct\fP field in the tty structure was not used and has been deleted.
        !            52: .XP tty_conf.c
        !            53: The line discipline close entries that used \fIttyclose\fP
        !            54: now use \fIttylclose\fP.
        !            55: The two tablet disciplines have been combined.
        !            56: A new entry was added for a Serial-Line link-layer encapsulation for the
        !            57: Internet Protocol, SLIPDISC.
        !            58: .XP tty_pty.c
        !            59: Large sections of the pseudo-tty driver have been reworked to improve
        !            60: performance and to avoid
        !            61: races when one side closed, which subsequently hung pseudo-terminals.
        !            62: The line-discipline modem control routine is called to clean up
        !            63: when the master closes.
        !            64: Problems with REMOTE mode and non-blocking I/O were fixed by using the 
        !            65: raw queue
        !            66: rather than the cannonicalized queue.
        !            67: A new mode was added to allow a small set of commands to be passed
        !            68: to the pty master from the slave as a rudimentary type of \fIioctl\fP,
        !            69: in a manner analogous to that of PKT mode.
        !            70: Using this mode or PKT mode, a \fIselect\fP for exceptional
        !            71: conditions on the master
        !            72: side of a pty returns true when a command operation is available to be read.
        !            73: \fISelect\fP for writing on the master side has been corrected,
        !            74: and now uses the same criteria as \fIptcwrite\fP.
        !            75: As the pty driver depends on normal operation of the tty queues,
        !            76: it no longer permits changes to non-tty line disciplines.
        !            77: .XP tty_subr.c
        !            78: The \fIclist\fP support routines have been modified to use block moves
        !            79: instead of \fIgetc/putc\fP wherever possible.
        !            80: .XP tty_tablet.c
        !            81: The two line disciplines have been merged and a number of new
        !            82: tablet types are supported.
        !            83: Tablet type and operating mode are now set by \fIioctl\fP\^s.
        !            84: Tablets that continuously stream data are now told to stop
        !            85: sending on last close.

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