Message-ID: <000301c263b3$649b7280$c03dfea9@atlantis>
From: "Matthias Paul" <Matthias DOT Paul AT post DOT rwth-aachen DOT de>
To: <opendos AT delorie DOT com>
References: <01FD6EC775C6D4119CDF0090273F74A4FD68B1 AT emwatent02 DOT meters DOT com DOT au>
Subject: Re: Combining DR-DOS 7.03 with OEM DR-DOS 7.05 to gain LBA capabilities
Date: Tue, 24 Sep 2002 11:54:10 +0200
Organization: Aachen University of Technology (RWTH), Germany
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Reply-To: opendos AT delorie DOT com

On 2002-09-24, Joe da Silva wrote:

> Well, this sound potentially interesting, but I must ask,
> does this overcome the "rename bug" of DR-DOS 7.04+?
> If so, then it is definitely interesting (otherwise perhaps
> not so interesting).

Yes, that's the whole point of using the DR-DOS 7.03 BDOS. :-)

This is oversimplyfied, but the DOS BIOS (IBMBIO.COM) contains
the loader, the hardware detection stuff, the CONFIG.SYS parser
(these are all transient portions) and the built-in resident
device drivers (character devices CON:, AUX:, PRN:, COM1:..COM4:,
LPT1:..LPT3:/LPT4:, CLOCK$:, and block devices A:..?:),
whereas the DOS kernel (IBMDOS.COM), that is the BDOS in DRI
terminology, contains all the DOS APIs, filesystem stuff, etc.
It's a quite clearly separated layered concept, otherwise
replacing some of these core components would not work...

So, by using the old BDOS, you can circumvent the Rename bug.
Of course, you will also loose FAT32 filesystem support.

The FDOS part of the BDOS does not deal with LBA in any way,
that's way too low-level for the kernel and is handled by the
DOS BIOS at device driver level. This is why using the new
IBMBIO.COM will give you LBA capabilities. The problem is
that the new BIOS will also try to log in FAT32 partitions
(create drive letters for them), and the old BDOS does not
know how to handle them. That's why FAT32 drives must be
avoided - or the code to log in such drives must be
patched dead.

Greetings,

 Matthias

-- 
<mailto:Matthias DOT Paul AT post DOT rwth-aachen DOT de>; <mailto:mpaul AT drdos DOT org>
http://www.uni-bonn.de/~uzs180/mpdokeng.html; http://mpaul.drdos.org

"Programs are poems for computers."