Timeline for answer to Unidirectional continuous data transfer to an air-gapped computer by user10216038
Current License: CC BY-SA 4.0
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9 events
| when toggle format | what | by | license | comment | |
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| Apr 7, 2021 at 3:58 | comment | added | MWB | Do data diodes have any advantages of the crippled serial port cable approach that @user4574 suggested? | |
| Dec 17, 2020 at 14:59 | comment | added | Navin | @user253751 I said "radiant energy density". If you focus a beam, the energy density goes up while the power stays the same. In other words, I've taken into account that the beam is more concentrated. btw the output is not totally invisible; Every module emits a small amount of visible light. This is a manufacturing defect, but it's very useful for debugging. Look for it the next time you're in a data center. To be clear, I'm talking about optics that you plug into switches. Higher power optics exist, but they are externally powered. That's probably what your instructor was talking about. | |
| Dec 17, 2020 at 5:55 | comment | added | Navin | @user253751 Have you ever used optics IRL? They are incredibly low power. Your typical 10km/40km SFP+ module has a lower IR radiant energy density than a light bulb. Don't spread FUD about laser safety | |
| Dec 16, 2020 at 2:33 | comment | added | Sam | Not sure if this is still relevent, but back when I was implementing this type of thing with fibre optic network cards nearly 20 years ago, they needed to see a carrier on the Rx port in order to send data out the Tx port. This meant you'd need a second card on your sending box looping back its Tx to the Rx of the card that you want to send data to the other box with. | |
| Dec 15, 2020 at 15:01 | comment | added | TooTea | @user253751 Not just for eye safety, but also to prevent said expensive transmitter from getting ruined by lots of dust getting in there. | |
| Dec 15, 2020 at 13:00 | comment | added | TooTea | Exactly. Given the bandwidth of a typical optical link, it's easy to send the same data 1000+ times (with a grown-up hash instead of a short checksum that can fail to detect some types of corruption) and thus practically eliminate the potential failed transfers. Just make it resend each data block every minute for 24 hours or so and you get something that's very resilient against all kinds of issues. | |
| Dec 14, 2020 at 23:02 | history | edited | user10216038 | CC BY-SA 4.0 |
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| Dec 14, 2020 at 22:54 | history | edited | user10216038 | CC BY-SA 4.0 |
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| Dec 14, 2020 at 22:44 | history | answered | user10216038 | CC BY-SA 4.0 |