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Comment on Paralyzed Jockey Loses Ability to Walk After Manufacturer Refuses to Fix Battery For His $100,000 Exoskeleton

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dgmib@lemmy.world ⁨1⁩ ⁨day⁩ ago

They call it jailbreak because this is an issue of freedom

I support your position and the right to repair, but that’s not the origin of the term jailbreak in the context of computing.

The term jailbreaking predates its modern understanding relating to smartphones, and dates back to the introduction of “protected modes” in early 80s CPU designs such as the intel 80286.

With the introduction of protected mode it became possible for programs to run in isolated memory spaces where they are unable to impact other programs running on the same CPU. These programs were said to be running “in a jail” that limited their access to the rest of the computer. A software exploit that allowed a program running inside the “jail” to gain root access / run code outside of protected mode was a “jailbreak”.

The first “jailbreak” for iOS allowed users to run software applications outside of protected modes and instead run in the kernel.

But as is common for the English language, jailbreak became to be synonymous with freedom from manufacture imposed limits and now has this additional definition.

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tabular@lemmy.world ⁨1⁩ ⁨day⁩ ago
Thanks for the history and technical explanation. I didn’t mean to imply that was the origin (for computing) and was only talking about a specific usage of the word.

I think most people say it to refer to manufacture imposed limits but I wanted to broad that idea. Using proprietary software is like being in a jail because your software freedoms are denied.

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- fmstrat@lemmy.nowsci.com ⁨1⁩ ⁨day⁩ ago
  Oooo healthy online discourse. Where’s my popcorn…
  
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  - AmbientChaos@sh.itjust.works ⁨23⁩ ⁨hours⁩ ago
    Lemmy is such a rad place, I love it here
    
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Schadrach@lemmy.sdf.org ⁨22⁩ ⁨hours⁩ ago

With the introduction of protected mode it became possible for programs to run in isolated memory spaces where they are unable to impact other programs running on the same CPU. These programs were said to be running “in a jail” that limited their access to the rest of the computer. A software exploit that allowed a program running inside the “jail” to gain root access / run code outside of protected mode was a “jailbreak”.

I still miss the narrow window in which you could make use of paging without technically being in protected mode. Basically there was like one revision of the 386 where you could set the paging bit but not protected mode and remain in real mode but with access to paging meaning you got access to paging without the additional processor overhead of protected mode. Not terribly useful since it was removed in short order, but neat to know about. Kinda like how there were a few instructions that had multiple opcodes and there was one commercially distributed assembler that used the alternative opcodes as a way to identify code assembled by it. Or POP CS - easily the most useless 80086 instruction, so useless that the opcode for it got repurposed in the next x86 processor.

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