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Floppy disks seem relatively volatile compared to other storage medium. If you're using a floppy disk, are the computers they're loading the data from even cap

Floppy disks seem relatively volatile compared to other storage medium. If you're using a floppy disk, are the computers they're loading the data from even capable of hashing the content and ensuring there is no corruption, or is the content signed?

nixass 6y ago
There must be post-checks or checklist to perform after the update. I doubt they go airborne with Gremlins under the hood (737MAX issues aside..)
- Jtsummers 6y ago
  Often, for software like this, you distribute a few pieces of data with the update. After it's installed the system runs and presents information like version number and the hash value of the binary (or binaries). You're supposed to verify these values as part of a checklist. Additionally, the primary host system can check that the hashed value presented is what it expects. How it handles it at that point may vary if it doesn't match, but at a minimum an error is displayed to the operators and stored in the logs. Since software isn't typically changed daily, this means verifying everything is updated once (update an LRU and update the corresponding portion of the host at the same time) and you're done for 6-18 months.
liability 6y ago
Error detection and correction codes have existed for decades, about as long as digital computers have. Do you have any evidence that this hypothetical flaw has ever actually caused trouble for a Boeing airplane? > capable of hashing Using a modern fancy hash? Maybe not, I'm not sure. But you can bet your ass they can at least work with hamming codes. They're probably doing a lot more validation than you seem to believe possible.
- linuxftw 6y ago
  I'm sure the CPUs are capable, physically, of running a checksum or hash, but that doesn't mean they are capable in the sense that it's capability exposed to the maintenance operator or generally part of the update system. Those systems probably have ECC memory, but who knows how many bits? And none of that helps you if the software you're loading into the system is corrupted in the first place. Any procedure that relies on a human to verify the data integrity is broken. Based on what we know today, the FAA is completely incompetent and Boeing does the absolute minimum required to get a plane off the ground. Why should I expect them to do literally anything? They need a top to bottom audit.
  - liability 6y ago
    These systems aren't new, they've been around for years. Much longer than the MAX. You have no citations for any of your fears; no examples of floppies causing problems for planes, no source to suggest there is no automated validation of data read off the disks, nothing. > Those systems probably have ECC memory, but who knows how many bits? And none of that helps you if the software you're loading into the system is corrupted in the first place My above comment had nothing to do with ECC memory. I am talking about using error correction codes with the data read off the disk, not merely to protect against corruption in RAM. That would catch the scenario where data is corrupted on the floppy before it ever touched the plane. If you have a source that suggests nothing of the sort is being done, then present it. Otherwise all you have is dumb speculation. And even if where the case that no verification is being done, that would be more a failure of the software than the floppy hardware. There's really nothing concerning about the use of floppies at all; if they were using modern flash instead I'd still expect them to be automatically verifying the integrity of all updates. Trusting flash is hardly less stupid than trusting a floppy. There is one big difference between using floppies and flash though; the floppy system has proven itself in the field and was created in past years hopefully before the FCC's recent dysfunction, while a flash system would not be proven in the field and would be created under an FCC known to be dysfunctional. This alone should be a great reason to not fix shit that isn't broken.
    - linuxftw 6y ago
nix23 6y ago
I trust a floppy much more than ANY usb-port/stick

nixass 6y ago

There must be post-checks or checklist to perform after the update. I doubt they go airborne with Gremlins under the hood (737MAX issues aside..)

Jtsummers 6y ago
Often, for software like this, you distribute a few pieces of data with the update. After it's installed the system runs and presents information like version number and the hash value of the binary (or binaries). You're supposed to verify these values as part of a checklist. Additionally, the primary host system can check that the hashed value presented is what it expects. How it handles it at that point may vary if it doesn't match, but at a minimum an error is displayed to the operators and stored in the logs. Since software isn't typically changed daily, this means verifying everything is updated once (update an LRU and update the corresponding portion of the host at the same time) and you're done for 6-18 months.

liability 6y ago

Error detection and correction codes have existed for decades, about as long as digital computers have. Do you have any evidence that this hypothetical flaw has ever actually caused trouble for a Boeing airplane? > capable of hashing Using a modern fancy hash? Maybe not, I'm not sure. But you can bet your ass they can at least work with hamming codes. They're probably doing a lot more validation than you seem to believe possible.

linuxftw 6y ago
I'm sure the CPUs are capable, physically, of running a checksum or hash, but that doesn't mean they are capable in the sense that it's capability exposed to the maintenance operator or generally part of the update system. Those systems probably have ECC memory, but who knows how many bits? And none of that helps you if the software you're loading into the system is corrupted in the first place. Any procedure that relies on a human to verify the data integrity is broken. Based on what we know today, the FAA is completely incompetent and Boeing does the absolute minimum required to get a plane off the ground. Why should I expect them to do literally anything? They need a top to bottom audit.
- liability 6y ago
  These systems aren't new, they've been around for years. Much longer than the MAX. You have no citations for any of your fears; no examples of floppies causing problems for planes, no source to suggest there is no automated validation of data read off the disks, nothing. > Those systems probably have ECC memory, but who knows how many bits? And none of that helps you if the software you're loading into the system is corrupted in the first place My above comment had nothing to do with ECC memory. I am talking about using error correction codes with the data read off the disk, not merely to protect against corruption in RAM. That would catch the scenario where data is corrupted on the floppy before it ever touched the plane. If you have a source that suggests nothing of the sort is being done, then present it. Otherwise all you have is dumb speculation. And even if where the case that no verification is being done, that would be more a failure of the software than the floppy hardware. There's really nothing concerning about the use of floppies at all; if they were using modern flash instead I'd still expect them to be automatically verifying the integrity of all updates. Trusting flash is hardly less stupid than trusting a floppy. There is one big difference between using floppies and flash though; the floppy system has proven itself in the field and was created in past years hopefully before the FCC's recent dysfunction, while a flash system would not be proven in the field and would be created under an FCC known to be dysfunctional. This alone should be a great reason to not fix shit that isn't broken.
  - linuxftw 6y ago

nix23 6y ago

I trust a floppy much more than ANY usb-port/stick