🚀 go-pugleaf

In <1992Aug18.021412.19094@news.ysu.edu> af458@yfn.ysu.edu (Jon K. Salmon) writes:

>Well, in theory you can look at the 4 WORD values at 40h:00h, which
>SHOULD be the port addrs for COM1-COM4.  How safe/reliable this
>technique is, I do not know.  There is a similar table of LPT port
>addrs (next 4 WORDs?  I don't recall), but I KNOW that is unreliable.

>For what it's worth...

>-- Jon
>-- 

Actually, the only time that I have found that looking for com/lpt base
port addresses in this manner fails is under Novell.  It does work under
every version of MS-DOS, Ntnx, Lantastic and PC-MOS.  When else have you
found it to be unreliable?

Another possible method is looking at the data at the standard port addresses
of 3f8,2f8,3e8 and 238 for comm ports and 3bc,378 and 278 for lpts.  This can
be pretty dangerous under a multitasking system of course :)

John
-- 
#include <disclaimer.h>			/* route all flames to /dev/null  */
/**************************************************************************/
/*   Systems Analyst      | John Steele     email: jsteele@netcom.com     */
/* Video Business Systems |                                               */
/*   1-800-255-3088       |    Most people spell COBOLSUX incorrectly...  */
/**************************************************************************/