Debug LPT/ COM

[sou]

Hi,

in this article http://www.wimsbios.com/phpBB2/viewtopic.php?t=1065
you can use dos and debug to fetch informations about COM and LPT.

When I use the Dos-Shell within Win98 these informations are correct.
(means: Ports which are not used are not registered)

Example: Dos-Shell Win98
C:\debug
-d 40:0 b
0040:0000 F8 03 00 00 00 00 00 00-78 03 00 00
-q

But when I'm calling debug within the Dos-Shell of XP
C:\debug
-d 40:0 b
0040:0000 F8 03 F8 02 E8 03 E8 02-BC 03 78 03
-q

Why are these results are so different?
The system (with XP) only has 2xCOM and 1xLPT.

Does the OS set virtual adresses or what's the reason?

Any ideas? Do I misunderstand something?

Thx

[NickS]

Does the OS set virtual adresses or what's the reason?

Yes. In 16-bit Windows the DOS prompt actually is a command shell that can access the hardware. In XP the "DOS box" is actually ntvdm, the NT Virtual DOS Machine. Find more info at Microsoft, here.

[sou]

Thx