From: drew@kinglear.cs.colorado.edu (Drew Eckhardt) Subject: Re: Can you access a virtual console directly? Date: 14 Sep 1992 17:49:31 GMT
In article <1992Sep14.164729.28907@mits.mdata.fi> kennu@mits.mdata.fi (Kenneth Falck) writes:
>Can you access a linux virtual console directly, something like what
>you usually do with MSDOS when writing characters and attributes to
>B800:xxxx?
Maybe, but you shouldn't.
>I think it might be useful for writing a terminal program that would
>be a bit more sophisticated than kermit or XComm. It feels a bit
>dumb to use termcap-codes to handle the local output, if you know
>you'll be using this terminal from the virtual consoles only.
There are MGR drivers for Hercules, EGA/VGA, and Trident SVGA boards.
There are free Xservers for the Tseng, Paradise PVG1, Genoa GVGA,
ATI boards, 8514/A, and EGA/VGA using the MFB code (Albeit some
are in alpha or beta form). Chances are that you may end up
running some windowing system with some terminal emulator on
your system. Of course, your program won't work with any of these.
You can pick up dumb terminals VERY cheap. Some places even give
them away. Of course, your program won't work with any of these.
If you use termcap or curses, your program will run on dec VT100's,
under the xterm client, under a MGR window, and even that Fubar4000
terminal that you picked up at the local ham/computer swap for $5.
It will also run on most other machines with the same curses library (ie SYSV
or Beserkly).
>I thought I might ask for advice, since if I succeed in writing a
>terminal program, I don't want it to break with the next kernel
>release because of using some odd non-fixed memory address or
>something...
If you want to write to the buffer directly, you'll have to write
/dev/kmem, using the addresses specified in the kernel NLIST. This is
non-portable, and there are no gurantees that the internal structures
won't change in the next release.
-- Microsoft is responsible for propogating the evils it calls DOS and Windows, IBM for AIX (appropriately called Aches by those having to administer it), but marketing's sins don't come close to those of legal departments. Boycott AT&T for their absurd anti-BSDI lawsuit.