Emulation (Was: Emulators of Classic Computers)

From: Vintage Computer Festival <vcf_at_siconic.com>
Date: Wed Jan 14 22:18:47 2004

On Wed, 14 Jan 2004, Damien Cymbal wrote:

> All this talk about emulators has got my juices flowing again.
> I use emulators alot, and have always been fascinated with machine
> emulation.
> It's always been a desire of mine to code up an emulator of my own for some
> box but I've never been confident enough in either my coding chops or
> understanding of really low-level machine details to think I could pull it
> off (I am an application programmer by day and have done little serious
> system-level and below coding).

Talk to Rich Cini. He would truly be an inspiration to you.

(To wit, Rich taught himself C programming so that he could write an
emulator for the Altair 8800.)

> Recently I've been toying with maybe trying to do something, but where to
> start? I picked a candidate like the Visual 1050 because my first thought
> was "there's alot of free existing, debugged code that can be utilized" i.e.
> no need to write a Z80 or 6502 core as there are quality ones available.
> Being a cpm machine would appear to be another plus in this area. And, I
> like this machine and I don't believe there is an existing emulator for it.

I thought the Visual 1050 was a DOS compatible machine (i.e. 8086
processor). I could be wrong.

> Now the part that I'm hoping someone who has written an emulator can shed
> some light on: how much machine docs/specs does one need to hope to have a
> fair shot at pulling this off successfully? For example, I'm pretty sure
> that there must be some 6502 ROM code somewhere in that box that provide
> graphic routines services. If you had a listing of this I'm sure that you'd
> be that further ahead towards your goal. Or even if you knew where it was
> mapping into memory you could at least dump it and disassemble it. Thing
> is, all the docs I have are user guide/usage type things which obviously do
> not go into these sort of technical details. I'm sure there are those that
> could reverse engineer the entire machine soup-to-nuts but it certainly
> seems like that is trying to find the needle in the haystack (which is maybe
> some of the fun?).

Reverse engineering the ROMs is a good start, and may be all you need.

Sellam Ismail                                        Vintage Computer Festival
International Man of Intrigue and Danger                http://www.vintage.org
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Received on Wed Jan 14 2004 - 22:18:47 GMT

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