[NTLK] 712000 patch

[Eckhart Köppen]

On Sat, 11 Jan 2025 09:10:48 -0800, Doug wrote:
> Eckhart,
> 
> Thanks.
> 
> Do you do your patching using Jump Redirection, Overlaying of Code Blocks,
> Memory Mapping, Data Patching, or some other method?

Pretty much all of the above :) I documented it back then here:

https://40hz.org/Pages/newton/hacking/newton-patches/

The ground work for this was done by Jonathan Kipling Knight (Prism 
Research), who reverse engineered the 717260 patch and documented how 
the Newton OS is using a combination of patchable jump tables and the 
memory management unit to allow updating the ROM after the fact. The 
overall approach is very clever, I haven't seen anything like this in 
the wild. It makes updatable devices cheaper since you can use lower 
cost ROM and need less flash. I suppose that could make the Newton also 
a good candidate for space exploration:)

> I can only imagine where your brain has to travel to to get this figured
> out and resolved.

Fortunately, I didn't have to sort out the foundations of a patch, but 
figuring out what to patch to fix the actual problem is still an 
interesting challenge!

> Does our collective maintaining of the Newton imply that we're maintaining
> a usage window around us and into the future which, simultaneously, implies
> that as we keep moving that window forward, all NTLK past users stuck in
> the past (past Doug as opposed to future Doug, for example) will somehow
> hypothetically have their Newtons break as our usage window is updated
> forward from the past and into the present and future?
> 
> I'm trying to restate the same thing slightly differently. As we maintain
> OS usage in the current moment, is it true that as we're maintaining it,
> were it applied to past users outside the usage window, theirs wouldn't
> work?

An interesting way to look at it, but yes, that's basically what it 
comes down to :)

So, dear time travelers from the past, update your Newtons before 
visiting us! And keep the Patch Remover ready when you go back!

Eckhart