Hola!
Si es cierto....
Pueden consultar la documentación del PCGPE que habla sobre el tema:
Esta en http://www.qzx.com/pc-gpe/
Hay muchos aspectos (a favor) que el modo X brinda con respecto de un simple modo 13h, por ejemplo se puede tener una resolución de 320x200x256 con 4 páginas.
Por el contrario la misma resolución en modo 13h solo brinda una página.
Tambien se obtiene resoluciones del tipo 320x240...
Puedes consultar el texto anterior para conocer como se establecen y manejan estas configuraciones.
Acontinuación un estracto de la introducción:
Title: INTRODUCTION TO MODE X
Version: 1.8
Author: Robert Schmidt
[email protected]>
Copyright: (C) 1993 of Ztiff Zox Softwear - refer to Status below.
Last revision: 25-Nov-93 (Modified for the PCGPE 17-Apr-94)
Figures: 1. M13ORG - memory organization in mode 13h
2. MXORG - memory organization in unchained modes
(Both files are appended to the end of this document)
The figures are available as 7-bit ASCII text (ASC) files.
Status: This article, its associated figures and source listings
named above, are all donated to the public domain.
Do with it whatever you like, but give credit where
credit is due.
The standard disclaimer applies.
Index: 0. ABSTRACT
1. INTRODUCTION TO THE VGA AND ITS 256-COLOR MODE
2. GETTING MORE PAGES AND PUTTING YOUR FIRST PIXEL
3. THE ROAD FROM HERE
4. BOOKS ON THE SUBJECT
5. BYE - FOR NOW
0. ABSTRACT
This text gives a fairly basic, yet technical, explanation to what, why
and how Mode X is. It first tries to explain the layout of the VGA
memory and the shortcomings of the standard 320x200 256-color mode,
then gives instructions on how one can progress from mode 13h to a
multipage, planar 320x200 256-color mode, and from there to the
quasi-standard 320x240 mode, known as Mode X.
A little experience in programming the standard VGA mode 13h
(320x200 in 256 colors) is assumed. Likewise a good understanding of
hexadecimal notation and the concepts of segments and I/O ports is
assumed. Keep a VGA reference handy, which at least should have
definitions of the VGA registers at bit level.
Throughout the article, a simple graphics library for unchained (planar)
256-color modes is developed. The library supports the 320x200 and
320x240 modes, active and visible pages, and writing and reading
individual pixels.