4 ms·

>it, instead of the traditional hardware that lets you completely overwrite everything in it if you have physical access. How do you plan to flash all the HDD/

by ksk 11y ago

>it, instead of the traditional hardware that lets you completely overwrite everything in it if you have physical access. How do you plan to flash all the HDD/USB/Network controllers? Not to mention the CPU/GPU microcode, and countless other random chips inside your computer that are executing firmware you have no access to. We're already hosed. Its just a matter of whats considered a 'reasonable' barrier.

kazinator 11y ago
If I have no access to the firmware, but neither does anyone else, then it's just a part of the hardware. That is okay. I don't care whether a given processor is microcoded via a tiny ROM, or whether it is all hard-wired gates; the difference is just in the instruction execution timings. We are not "hosed" in any way by this. As soon as the microcode is writable, then we have questions: can anyone write any arbitrary microcode and put it in place? Or is there some tamper-proof layer containing that only accepts signed microcode, and who has the keys?
- ksk 11y ago
  >If [...] but neither does anyone else, then it's just a part of the hardware That has never been the case, for practical manufacturing reasons. >As soon as the microcode is writable, then we have questions: It has been writable for more than a decade I think.
  - kazinator 11y ago
    Uh, microcode has been around since the 1960's! Any aspect of the machine which is data-driven is de facto hardware if that data is fixed in read-only memory. Consider than an AND gate can just be memory. The two inputs can be treated as a two bit address: 00, 01, 10, or 11. If we stuff in the values 0, 0, 0, 1 into the 1-bit content cells at these addresses, we have an AND gate. If this memory is ROM, then the overall circuit is not distinguishable from a conventional AND gate where a few transistors do the signaling directly.

4 ms·

>it, instead of the traditional hardware that lets you completely overwrite everything in it if you have physical access. How do you plan to flash all the HDD/

by ksk 11y ago

kazinator 11y ago
If I have no access to the firmware, but neither does anyone else, then it's just a part of the hardware. That is okay. I don't care whether a given processor is microcoded via a tiny ROM, or whether it is all hard-wired gates; the difference is just in the instruction execution timings. We are not "hosed" in any way by this. As soon as the microcode is writable, then we have questions: can anyone write any arbitrary microcode and put it in place? Or is there some tamper-proof layer containing that only accepts signed microcode, and who has the keys?
- ksk 11y ago
  >If [...] but neither does anyone else, then it's just a part of the hardware That has never been the case, for practical manufacturing reasons. >As soon as the microcode is writable, then we have questions: It has been writable for more than a decade I think.
  - kazinator 11y ago
    Uh, microcode has been around since the 1960's! Any aspect of the machine which is data-driven is de facto hardware if that data is fixed in read-only memory. Consider than an AND gate can just be memory. The two inputs can be treated as a two bit address: 00, 01, 10, or 11. If we stuff in the values 0, 0, 0, 1 into the 1-bit content cells at these addresses, we have an AND gate. If this memory is ROM, then the overall circuit is not distinguishable from a conventional AND gate where a few transistors do the signaling directly.