Re: Commodore PLC TIB DD-001 / Drive 2001

From: Ruud_at_Baltissen.org
Date: Mon, 19 Nov 2018 22:11:37 +0100
Message-ID: <5BF32709.18232.DC5AA1@Ruud.Baltissen.org>
Hallo allemaal,
 
 
> Even more frustrating: I thought about using a commented source of 
> the BIOS of the IBM PC and one of a clone....

I just found out that something went wrong with naming and placing 
some files 14 years ago. I was sure I missed something in the IBM 
source so I checked a PDF of the reference manual of the PC-XT. That 
gave me a keyword, "diskete_io" in this case, and searching for this 
string in all my ASM files gave me the correct source file. This 
source is quite clear what is done when handling a FD. Just take in 
mind that a PC uses DMA to transfer data so a) this "polutes" the 
source quite a bit and b) things can differ for the non-DMA mode.

If someone is interested in this file, email me and I will upload it 
to my site.

FYI: this was my very first commented disassembly somewhere in 1985 
or 1986 using the original comment of IBM from this manual. I used 
it as base to create my own BIOS so I could diagnose faulty boards. 
Saved and earned my company quite some money in those days. For the 
ATs and better we bought a tool called Logimer.


--
   
Kind regards / Met vriendelijke groet, Ruud Baltissen
www.Baltissen.org







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Received on 2018-11-19 23:00:07

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