NAME

/dev/console − Amiga console device

SYNOPSIS

#include <sys/types.h>
#include <sys/amiga/screen.h>
int fd;
fd = open("/dev/console", mode);

DESCRIPTION

/dev/console, /dev/con1, /dev/con2, ..., are special files which, when opened, give access to a screen which will appear to be an ANSI-compatible terminal.  If there already exists a screen corresponding to the opened name, fd will refer to it, otherwise fd refers to a newly created screen.  This screen is a tty device as described in termios(7), and may be used as a login terminal or for any purpose for which a display terminal is normally used.  It is also a streams device and is suitable for streams functions described in streamio(7). 

When a new console screen is created, it is not displayed by default.  Before it is displayed, certain parameters such as graphics modes and pixel resolution may be specified using the SIOCSETTYPE ioctl (see screen(7A)).  Once a console screen has been written to or displayed, its graphics modes and resolution are fixed until it is closed. 

A console screen is a "virtual" screen, meaning that it can be accessed without regard to the existence of other screens, and regardless of whether it is being displayed at the moment.  There can exist many screens, some of which might be other similar console screens, and the user can select which one is "active" using the keyboard or mouse (currently only the ALT-function-key selection method is supported). 

Read and write system calls are used to do I/O to the screen as with any termios device.  Input will be codes from the ASCII/ISO character set, possibly including ANSI control sequences representing special keys such as the arrow keys and function keys.  Output is displayed as ASCII/ISO characters with ANSI control sequences interpreted for such functions as cursor positioning, attribute setting and insertion/deletion.  See the terminfo entry for ‘amiga’ for a description of the codes recognized. 

When the console screen is closed using the close(2) or _exit(2) system calls, and no process has that console screen open, the screen will cease to exist and its memory will be released for use by other programs.  One exception to this is /dev/console,theconsolescreenwhich it is starting up.  This screen will never go away unless no process has it open and the HUPCL bit is turned on in its termios parameters.  Even if it does go away, it will come back any time the Unix kernel needs to display a message.  In addition, /dev/console’s screen will "pop to the front" of other screens (force itself to be displayed) in the case of a kernel "panic" (when a fatal error has occurred and the system is stopping).

Console screens use the Amiga’s "chip" memory, the special 16-bit wide memory that is accessible by the graphics custom chips.  This memory is not virtual, so the number of screens that can exist at one time is limited by the amount of chip memory in the system.  This is usually 512K to 2M bytes. 

IOCTL COMMANDS

In addition to the functions described in termios(7) and streamio(7), the console device supports the following ioctl commands from screen(7A):

SIOC, SIOCDISPLAYTYPE, SIOCFRONT, SIOCBACK, SIOCACTIVATE, SIOCSETKMAP, SIOCGETKMAP, SIOCSETDEFKMAP, SIOCSETFONT, SIOCGETFONT, SIOCSETDEFFONT, SIOCSETTYPE, SIOCGETTYPE, SIOCWINSIZE, SIOCSETDISPLAYTYPE. 

BUGS

Multiple bitplanes are permitted but ignored (only bitplane zero is ever modified).  ECS modes are not supported yet.

FILES

/dev/console, /dev/term/con[1-9] - special files for accessing console screens

SEE ALSO

open(2), close(2), ioctl(2), read(2), write(2), termios(7), streamio(7), amiga(7A), screen(7A). 

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