Date: Sun, 26 Nov 1995 09:24:04 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Kuang-chun Cheng <kccheng AT hycpsg01 DOT fnal DOT gov>
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: need help


On 24 Nov 1995, Kuang-chun Cheng wrote:

>    I am using DJGPP for a driver of a interface board on 386 which run
>    under DOS 6.2.  The interface board have 16K momary mapped on PC ISA
>    bus 0xc4000~0xc7fff.  I simply create a pointer to access, said, 0xc4000
>    directly.  But I got a segmentation error like,
> 
>       Segmentation violation at pointer 0xc4000 in df:13f7
>       cs=df  ds=48  es==48 ....

Get the DJGPP FAQ list (faq102.zip from the same place you get DJGPP) and 
read Chapter 10 and Chapter 18.  They explain this and related issues.  
(You cannot just poke any arbitrary address under DJGPP which is a 
protected-mode environment.)