![[BACK]](/cvsweb/icons/back.gif){kind=icon}
Return to cons.4 CVS log ![[TXT]](/cvsweb/icons/text.gif){kind=icon}
![[DIR]](/cvsweb/icons/dir.gif){kind=icon}
Up to [CSRG BSD Unix] / 43BSDTahoe / new / X / libibm / doc / man|
Return to cons.4 CVS log | Up to [CSRG BSD Unix] / 43BSDTahoe / new / X / libibm / doc / man |
1.1 root 1: .\"$Header: cons.4,v 10.1 86/11/19 10:55:30 jg Exp $
2: .\"$Source: /u1/X/libibm/doc/man/RCS/cons.4,v $
3: .\" This file uses -man macros.
4: .TH CONS 4 "31 Mar 1986" "Space overwritten by .AC macro" " "
5: .UC 4
6: .AC 1 0
7: .SH NAME
8: cons \- keyboard and console display interface
9: .SH DESCRIPTION
10: The keyboard and various possible displays combine to
11: provide a terminal-like
12: interface to the system. Internally, these are separate devices which
13: software combines to emulate a normal terminal. See the appropriate manual
14: pages for information about each display and the keyboard.
15: .PP
16: The keyboard adapter also supports the speaker, which is activated
17: when the ASCII character \fBbel\fP
18: .RB ( ^G )
19: is sent to the display via software.
20: .PP
21: .B Console Device Control.
22: .PP
23: The display devices,
24: \fI/dev/ttyaed\fR, \fI/dev/ttymono\fR, \fI/dev/ttyap16\fR,
25: \fI/dev/ttyapa8\fR, and \fI/dev/ttyap8c\fR are all
26: minor devices under
27: \fI/dev/console\fR, and are all capable of displaying console
28: output. Uniq to this system is the fact that you may have one or more of these
29: displays on your workstation at a time and any one can act as a console.
30: Since we only have one keyboard and system mouse the console driver
31: multiplexes these two input devices to the many displays.
32: All of the displays may have simultaneous logins and the user
33: may "hot key" between each display.
34: At first, this
35: .I Input focus
36: is on
37: the first device in the above sequence to
38: be found at initialization time. The input focus
39: may be manually switched to the next available display by hiting the
40: default "hot key"
41: .I <F12>.
42: When the
43: .I input focus
44: is on a display all keyboard and mouse data will be sent to the process
45: which opened that display.
46: .PP
47: If a process opens
48: .I /dev/console
49: it gets assigned to whatever the
50: .I input focus
51: was at the time of the open.
52: A user can forward console messages to any tty/display with the
53: TIOCCONS ioctl.
54: .PP
55: In order to support the many displays and the multiplexing between them an,
56: \fIEmulator Package\fR was developed to work with the console driver.
57: This package allows different types off emulation on input and output to
58: be written device independently.
59: .PP
60: The display devices,
61: \fI/dev/aed\fR, \fI/dev/mono\fR, \fI/dev/apa16\fR,
62: \fI/dev/apa8\fR, and \fI/dev/apa8c\fR are all
63: .PP
64: Should a user-process open the current console display
65: (thus making it unavailable for console use), the console output
66: switches to the next available display. A device is
67: available if it is present, not already open, and access has not been
68: denied (as described below.)
69: .PP
70: Should no display be available to serve as console,
71: console output is stored in a system-provided circular buffer.
72: Once the user-process completes, the display is reopened as a
73: console and the buffer contents are flushed to the display.
74: .PP
75: .B Controlled access to multiple console displays.
76: .PP
77: It can be useful to deny access temporarily to one or more displays.
78: For example, if the monochrome/printer adapter is present, the kernel
79: assumes the presence of the monochrome display -- even if disconnected -- and
80: attempts to initialize it. This can be blocked by modifying the access
81: control bits for each display device (see
82: \fI<machinecons/consio.h>\fR):
83: .PP
84: .DT
85: CONSDEV_KERNEL (this device available to kernel)
86: .br
87: CONSDEV_USER (this device available to user)
88: .PP
89: An ioctl, SCRIOCSETC (screen ioctl:set configuration), sets
90: the desired access rights of a particular device.
91: SCRIOCGETF (screen ioctl:get flags) gets
92: the present state of a particular device:
93: .PP
94: .DT
95: CONSDEV_PRESENT (kernel has detected adapter)
96: .br
97: CONSDEV_KERNEL
98: .br
99: CONSDEV_USER
100: .br
101: CONSDEV_INIT (device is initialized for console use)
102: .br
103: CONSDEV_OPEN (device is opened for user access).
104: .PP
105: These ioctls are used by \fIsetscreen\fR(8).
106: .SH NOTE
107: The kernel flashes ``98'' on the LEDs if it cannot find any
108: configured display during initialization, and then proceeds.
109: .SH FILES
110: /dev/console
111: .br
112: /dev/mono
113: .br
114: /dev/apa8
115: .br
116: /dev/apa16
117: .br
118: /dev/aed
119: .SH "SEE ALSO"
120: ibm5151(4), ibm6153(4),
121: ibm6155(4), ibmaed(4), keyboard(4),
122: tty(4), setscreen(8)
123: .br
124: .SH DIAGNOSTICS
125: None.
This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.