Reverse Engineering

Anything QL Software or Programming Related.
Derek_Stewart
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Reverse Engineering

Postby Derek_Stewart » Tue Jan 21, 2020 2:17 pm

Hi,

I am wondering whether reverse engineering, which involve software disassembly of QL software where the source code is not available is legal or not.


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Derek
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RalfR
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Re: Reverse Engineering

Postby RalfR » Tue Jan 21, 2020 2:34 pm

I think, you should ask the copyright owner (mostly the author). If the source code is lost (DM5 or QLiberator), perhaps they are very pleased, if you are able to help them out.


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tofro
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Re: Reverse Engineering

Postby tofro » Tue Jan 21, 2020 2:58 pm

Derek_Stewart wrote:Hi,

I am wondering whether reverse engineering, which involve software disassembly of QL software where the source code is not available is legal or not.


Derek,

you are aware that's a really big can of worms you're opening? :D I'm not a lawyer, but have been working in the software industry for some time, so feel entitled to a very non-exhausting answer.

In most legislations it isn't - Just like ripping apart your alarm clock to see how it works isn't.

It might, however, be (and in most cases is) a breach of your licence contract, if it explicitly says so.

There's more traps to fall into when recompiling the reengineered source code back into a product and do something (like sell it or otherwise transfer it to a third party) with it, or more generally, what you do with the gained insights:

  1. In some legislations, you might be commiting patent infringement (assuming such a patent exists) - Some legislations allow source code to be patented (US of A, for example says "anything under the sun that is made by man" can be patented) while many others, especially in Europe, don't and explicitly exclude software from the list of things that can be patented.
  2. You will very probably commit copyright infringement when you copy the whole thing 1:1 or in large parts (which is very hard to proof without reengineering your product, see above...)
  3. Provided your product looks and claims to be the original or like the original, you might be committing product piracy, breaching all sorts of international trade agreements
  4. and many more

Tobias


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Pr0f
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Re: Reverse Engineering

Postby Pr0f » Tue Jan 21, 2020 3:33 pm

I agree - rework or making a copy using the source to make another comercial product would infringe the legality.

But we see a lot of books on disassembly of the spectrum roms for instance - I presume these must have been given legal authority to publish?


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XorA
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Re: Reverse Engineering

Postby XorA » Tue Jan 21, 2020 3:38 pm

tofro wrote:[*]In some legislations, you might be commiting patent infringement (assuming such a patent exists) - Some legislations allow source code to be patented (US of A, for example says "anything under the sun that is made by man" can be patented) while many others, especially in Europe, don't and explicitly exclude software from the list of things that can be patented.


That is highly unlikely with QL software though given the typical duration of patents ;-)


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tofro
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Re: Reverse Engineering

Postby tofro » Tue Jan 21, 2020 3:58 pm

Pr0f wrote:I agree - rework or making a copy using the source to make another comercial product would infringe the legality.

But we see a lot of books on disassembly of the spectrum roms for instance - I presume these must have been given legal authority to publish?


Well, if I had been Sinclair Research at that time, I would have been happy to see books that boost software availability for my computers back in the day.....

No case, no judge, as they say.

Tobias


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janbredenbeek
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Re: Reverse Engineering

Postby janbredenbeek » Tue Jan 21, 2020 4:22 pm

Pr0f wrote:I agree - rework or making a copy using the source to make another comercial product would infringe the legality.
But we see a lot of books on disassembly of the spectrum roms for instance - I presume these must have been given legal authority to publish?

The Spectrum never came with a licence contract containing dozens of pages with legalese telling you not to disassemble the ROM :D
Of course, the code was covered by the applicable copyright laws. But AFAIK Sinclair has never objected to these publications (they were probably even happy with them as there was virtually no official documentation on using the ROM routines in your own machine code).
I remember the Apple II manual even contained (part of) a listing of the source code of the ROM. It was a totally different time then.

As for Sinclair/Amstrad, it is well-known that they have given permission to use the ROM code in emulators (even in modified form), but not in hardware products. I remember when buying Minerva you had to prove you owned a QL by sending a cartridge containing the ROM code. The Gold Card contained code which patched the original ROM rather than replacing it completely.

Jan


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RalfR
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Re: Reverse Engineering

Postby RalfR » Tue Jan 21, 2020 6:49 pm

janbredenbeek wrote:The Gold Card contained code which patched the original ROM rather than replacing it completely.

Same with the first hardware Atari emulator from Futura Datasenter, they just supplied a QDOS disk for patching your saved ROM code.


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tofro
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Re: Reverse Engineering

Postby tofro » Tue Jan 21, 2020 7:02 pm

Ralf R. wrote:
janbredenbeek wrote:The Gold Card contained code which patched the original ROM rather than replacing it completely.

Same with the first hardware Atari emulator from Futura Datasenter, they just supplied a QDOS disk for patching your saved ROM code.


I'm pretty sure that (both) was legal at that time and would be legal even today.

Tobias


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EmmBee
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Re: Reverse Engineering

Postby EmmBee » Tue Jan 21, 2020 9:25 pm

How about QL software such as CPORT and CFIX?
Both have been compiled with Turbo but published without their sources.
We have tried to make contact with the authors/copyright owners but without success.
Interest has been shown in obtaining the sources on this forum.
These products are now not available to buy anymore.
Would it be illegal to decompile them?
The benefit of decompilation is that they could be updated to run on modern systems.



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