Re: VT100 alternate character set support for the Mac OS X/Darwin console ("xnuppc-acs"/"darwin-acs")

[Thomas Dickey]

On Sat, 12 Jan 2008, Ben Wiley Sittler wrote:

> It turns out that it is possible to fix the Mac OS X console font at
> boot-time to include the VT100 alternate character set in
> previously-vacant positions. I have written a script to automate this,
> and added a few more terminfo entries to the xnuppc/darwin family. The
> new variants have names ending in "-acs", e.g. darwin-acs or
> xnuppc-acs. The script and the terminfo are attached to this message,
> and they're also available here:
>
> http://zoehep.xent.com/~bsittler/mach_acs
> http://zoehep.xent.com/~bsittler/xnuppc.ti
>
> The script is so far only tested on Mac OS X 10.4 running on a 32-bit
> Intel processor, but the same technique should work elsewhere too.

thanks (it's interesting to read)

> NOTE: The script works by patching the kernel at boot-time. This is
> potentially risky, but I've tried to do it robustly: the script uses
> 'nm' to look up the '_iso_font' symbol in the kernel image, then
> checks to make sure the font positions it's about to overwrite were
> previously all nulls, and only then writes to kernel memory. It also
> uses /dev/kmem, which is not enabled by default, but is enabled by the
> script's installation steps (using the kmem=1 nvram boot-args
> parameter).
>
> -Ben

--
Thomas E. Dickey
http://invisible-island.net
ftp://invisible-island.net