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Continuation of HAZE and ark-adr's legal conversation re: MAME, etc.

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Haze:


--- Quote from: mcseforsale on August 09, 2013, 10:18:00 am ---
--- Quote from: Haze on August 09, 2013, 10:13:35 am ---
--- Quote from: Sjaak on August 09, 2013, 10:09:00 am ---
--- Quote from: ark_ader on August 09, 2013, 09:59:41 am ---
You will like this one Haze.


--- End quote ---

I may have this all wrong, but isn't that article about reverse enigneering a game (or in this case a part of a game).

I always thought that Mame emulates hardware (like for example the Z80 processor) and not the actual games.

--- End quote ---

We figure out the hardware often by looking at the access patterns of the software trying to use that hardware.  What we ship emulates the hardware.


--- End quote ---

this part fascinates me ^^

--- End quote ---

SW clears a large region of memory address spaces, it's probably ram.
SW writes what appears to be a 32x32 grid of data there, it's probably a tilemap
SW writes a short list of variable length 4-byte entries, it's probably a sprite
SW polls an address, it's probably some kind of io port
SW writes an address with single bits alternating / flipping, some kind of ouput
SW does the same but polls a read address between writes, could be some kind of serial port / eeprom

etc.

obviously it's a little more complex than that, but you get the idea.  we don't actually have to know what the purpose of every bit of code in the software is, nor understand any of the internal game logic, we just have to understand the interactions it is attempting to make with the hardware and what they mean, then implement the emulation of what is there in code.

this of course assumes you already have a working CPU core etc. otherwise you've got a lot more work to do.  luckily one of the many valuable resources contained within MAME is a vast library of well tested CPU cores.

jdbailey1206:


--- Quote from: Sjaak on August 09, 2013, 10:21:33 am ---
--- Quote from: jdbailey1206 on August 09, 2013, 10:13:15 am ---No Sjaak.  You're wrong.  It emulates the hardware.  Not the game....

--- End quote ---

That's what I thought.

I don't see the legal issues with emulating hardware (from a common sense point of view).

In fact, in my line of work we sometimes use commercial terminal emulation software on windows to access legacy systems because nobody has a working VT-100 terminal anymore. This software emulates all kinds of stone age terminals.

This emulation software is used by hospitals, airlines, etc. to access legacy systems, which would otherwise become unusable.

--- End quote ---

Sjaak?  Or do you go by your real name...Miles Dyson!?!

So its your fault for the T-101!  How could you release such a monstrous evil on to the world?   :angry:  Oh...wait.  VT-100.  Nevermind. 

Sjaak:


--- Quote from: jdbailey1206 on August 09, 2013, 10:29:06 am ---So its your fault for the T-101!  How could you release such a monstrous evil on to the world?   :angry:  Oh...wait.  VT-100.  Nevermind.

--- End quote ---

The VT-100 Terminator emulation software is still in beta, but will be released soon.  ;D

ark_ader:


--- Quote from: Haze on August 09, 2013, 10:25:09 am ---
--- Quote from: mcseforsale on August 09, 2013, 10:18:00 am ---
--- Quote from: Haze on August 09, 2013, 10:13:35 am ---
--- Quote from: Sjaak on August 09, 2013, 10:09:00 am ---
--- Quote from: ark_ader on August 09, 2013, 09:59:41 am ---
You will like this one Haze.


--- End quote ---



I may have this all wrong, but isn't that article about reverse enigneering a game (or in this case a part of a game).

I always thought that Mame emulates hardware (like for example the Z80 processor) and not the actual games.

--- End quote ---

 We figure out the hardware often by looking at the access patterns of the software trying to use that hardware.  What we ship emulates the hardware.


--- End quote ---

this part fascinates me ^^

--- End quote ---

SW clears a large region of memory address spaces, it's probably ram.
SW writes what appears to be a 32x32 grid of data there, it's probably a tilemap
SW writes a short list of variable length 4-byte entries, it's probably a sprite
SW polls an address, it's probably some kind of io port
SW writes an address with single bits alternating / flipping, some kind of ouput
SW does the same but polls a read address between writes, could be some kind of serial port / eeprom

etc.

obviously it's a little more complex than that, but you get the idea.  we don't actually have to know what the purpose of every bit of code in the software is, nor understand any of the internal game logic, we just have to understand the interactions it is attempting to make with the hardware and what they mean, then implement the emulation of what is there in code.

this of course assumes you already have a working CPU core etc. otherwise you've got a lot more work to do.  luckily one of the many valuable resources contained within MAME is a vast library of well tested CPU cores.

--- End quote ---

The SW hooks.  ::)

OK so why is there protections in the ROM?  Is it deliberate act to slow people down or stop them copying their code?  What about hardware like the main boards, Mame is emulating them too?

Let us cut to the chase.  I'm all for preservation and it is needed for all those arcade games from 1970-1985.  Most of the copyright holders do not care, and if they did well it would stop your party pretty quickly.  I am focusing these recent articles on your new baby.  This Universal Mame.  Sorry for not connecting the dots for you.

The gang is not satisfied with a certain era of forgotten gaming, but now concentrating on recent consoles.  ::)

I was having a chat with a colleague about this as he likes classic gaming, and feels that there should be an amnesty on all copyright violations involving emulation.  Which sounds great in theory.

We just have one small problem though.  It would also justify your Chinese pals who create these Xn1 boards.  That shouldn't ever happen.  At least Mame shows the copyright holders name.  Besides anyone can (and do) use mame for commercial purposes.  Just find a PC and fire up a rom and stick it in a cabinet (if they own the main board or game on a different platform, can justify it) as a backup.  That is the crux of the whole argument.  Mame in principal should not allow the games to be played, it is a nice side effect..... :lol

The project is supposed to be about documenting.  Where are these documents?  The schematics of the individual game hardware for people to share and learn?  Or help people with IP ownership to maybe use your valued help (as you have provided in earlier posts) to create a anniversary cabinet with a custom board set or fix an old one?

We can talk about this all year long, but the biggest problem is not the act, but the distribution of the protected items on the internet.  With this prism project in the papers recently, it wouldn't be that hard finding the offenders, well the ISP will be responsible as they are the providers essentially.

Not answering my questions?  I'm not bothered.  Your silence works better for me.

The problem with Haze, that he will give up his secrets.  Just keep him in conversation long enough.   ;D


::::

Sjaak:

Do you have a link for this VT100 emulator? Pricing for volume licensing too.

Thanks

Vigo:


--- Quote from: ark_ader on August 09, 2013, 11:05:58 am ---Let us cut to the chase.  I'm all for preservation and it is needed for all those arcade games from 1970-1985.

--- End quote ---


You keep bringing up the fact that you think that games from 1998 or so should not be included because they are too new. What measure are you exactly using to determine what is acceptable to preserve and what is not? As far as I can tell, many of these games are still quite often obscure and still live with the threat of being lost in the near future. I think you are not looking at the big picture, here. Also, can you say for certain what the climate will be like in 10 years?

From haze's blog, the latest find is a 94 game called Cassanova. I never heard of it, and it seems like it is a completely obscure title. From your measure of 1985 as the latest current acceptable date, (28 years), The MameDev team would have to wait until the year 2022 to procure and preserve this title. Can you say for certain this title will be available to find 10 years from now? If you can make a strong case that these titles are all living a safe, unthreatened existance, I might agree with you, but all the games he has been covering on his blog recently are pretty darn old or rare sounding to me.

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