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Mail Archives: djgpp/1997/09/25/16:22:17

Message-Id: <m0xEEkZ-000S1yC@inti.edu.ar>
Comments: Authenticated sender is <salvador AT natacha DOT inti DOT edu DOT ar>
From: "Salvador Eduardo Tropea (SET)" <salvador AT inti DOT edu DOT ar>
Organization: INTI
To: nambi AT club-internet DOT fr, djgpp AT delorie DOT com
Date: Thu, 25 Sep 1997 17:22:05 +0000
MIME-Version: 1.0
Subject: Re: FAR POINTERS

Charles Mennerat <nambi AT club-internet DOT fr> wrote:

Pedantic questions can be answered pedantic? ... I'll be kind with you.

> In WIN95 they are no more use of far pointers.(in France)
Wrong, why do you think it?
1) Win95 uses TONS of 16 bits code so Win95 is FULL of far pointers.
2) Do you know the what a far pointer is?, It's a pointer where you specify 
both segment (selector) and offset. So any 32 bits protected mode OS will use 
far pointers!, or do you think the memory model of Win95 is a 100% flat one?. 
Think about it: If you have a 100% flat memory model with cs=ds=... and all 
with 4Gb of limit then you can write over the kernel!. Win95 is bad designed 
... but no so bad. A native Win95 application isn't able to write over the 
kernel. 

> In djgpp they are still used.
Because in this way is much harder to destroy the OS from the program.

> Both of then use all the ram all the ram of your computer if necessary.
Of course.

> As a conclusion i would say use microsoft(very funny,isn't it?) 
Not funny at all.

> What are far pointers,
Selector:OffSet pointers.
> when are they usefull.
When you can access to memory outside the space reserved for your program, for 
example to access the video memory.

>If you try to work
> in other memory block then the one you're working in is that what far
> pointers are usefull for?
Ah?, can you reorder this sentence?

SET 
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Salvador Eduardo Tropea (SET). (Electronics Engineer)
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