🚀 go-pugleaf

Hi, I am wondering if someone can help me with what should be
an easy problem, I think, but I can't find the answer.

I am interested in using text modes 0-3 with an alternate character
set.  I just bought an MS-DOS book, by the Waite Group assuming that it
would be good, because I really liked their C- Bible.  And it has been
good, regarding memory management, device drivers, graphic modes and 
other things, but it has said near nothing about text modes with color
or altering the character set.

For some reason I am under the impression that character 00h-7Fh are
not alterable, but characters 80h-FFh are alterable.  I don't 
know why I have this impression, I just do and it may be completely wrong.
Could someone straighten me ought, and also explain how one would go
about changing these, especially in C, but I would appreciate any
solution.

Also, how is color handled in the text modes.  I was given the imprsesion
that a text lines is 80 bytes.  This does not leave room for color, or is
this latched bit planes like the EGA?

Please someone help, with either a BIOS solution or direct or both.
Thanks in advance for your help.

Mitch Dernis