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If I remember correctly, the book addressed this. 26 division of a circle was too much for reliable determination of which sign the camera was pointing at, so 1

by hoten 2y ago

If I remember correctly, the book addressed this. 26 division of a circle was too much for reliable determination of which sign the camera was pointing at, so 16 (hex) made the angles more workable. If we're talking efficiency, I wonder why he didn't consider Morse code. Well I guess that's easy, even though it's faster it takes a skilled operator to read it in realtime, and he had little time to write any individual bit of information down (cumbersomely writing in sand is slow)

Thorrez 2y ago
You can't represent 26 possibilities with a single hex digit. So it'll require 2 hex digits. If you're going to require 2 digits, then that can be done with 2 decimal digits as well. So there's no need for hex, and no need for ascii tables. However, if you need more than just the 26 letters, e.g. if you also need numbers and/or punctuation, then ascii might be useful, and hex might be useful to encode ascii into 2 digits.
- vasco 2y ago
  If I send you this: 48697468657265 Why do I need to send it to you 2 digits at a time? It's valid hex that converts to ascii, only 1 symbol at a time, which is how he communicated. He could've done it with just a card for 0 and another for 1 if he really wanted.
  - Thorrez 2y ago
    I didn't say it needs to be sent 2 digits at a time. The points of my previous comment: * Ascii is only needed if we need to encode things other than just letters (or if case matters). * Hex is only better than decimal if hex allows the number of digits to be reduced. If we need to only encode 26 elements, then hex doesn't reduce the number of digits compared to decimal, so hex has no advantage over decimal in the 26-element case. Using just 0 or 1 will increase the number of digits needed, so has a clear disadvantage compared to hex or decimal.
    - vasco 2y ago
      > Hex is only better than decimal if hex allows the number of digits to be reduced. If we need to only encode 26 elements, then hex doesn't reduce the number of digits compared to decimal, so hex has no advantage over decimal in the 26-element case He had more than 26 things to encode, I believe he started with numbers, letters and a question mark. > Using just 0 or 1 will increase the number of digits needed, so has a clear disadvantage compared to hex or decimal Using 0 or 1 decreases that to only 3 cards (including question mark), and increasing the safety margin to 120° on the setup he had. It'd take longer but be more robust.
      - Thorrez 2y ago
        >He had more than 26 things to encode Ok, then hoten's comment had an error which propagated to my comments: >26 division of a circle was too much for reliable determination of which sign the camera was pointing at
- shortrounddev2 2y ago
  He later painstakingly translates machine code transmitted via the camera to the rover which patches the software to allow him to chat via text, so hex came in handy
unsupp0rted 2y ago
Too bad he didn't know Hangul (Korean writing system). He could have managed to communicate well enough with half a dozen chars.

by hoten 2y ago

Thorrez 2y ago

You can't represent 26 possibilities with a single hex digit. So it'll require 2 hex digits. If you're going to require 2 digits, then that can be done with 2 decimal digits as well. So there's no need for hex, and no need for ascii tables. However, if you need more than just the 26 letters, e.g. if you also need numbers and/or punctuation, then ascii might be useful, and hex might be useful to encode ascii into 2 digits.

vasco 2y ago
If I send you this: 48697468657265 Why do I need to send it to you 2 digits at a time? It's valid hex that converts to ascii, only 1 symbol at a time, which is how he communicated. He could've done it with just a card for 0 and another for 1 if he really wanted.
- Thorrez 2y ago
  I didn't say it needs to be sent 2 digits at a time. The points of my previous comment: * Ascii is only needed if we need to encode things other than just letters (or if case matters). * Hex is only better than decimal if hex allows the number of digits to be reduced. If we need to only encode 26 elements, then hex doesn't reduce the number of digits compared to decimal, so hex has no advantage over decimal in the 26-element case. Using just 0 or 1 will increase the number of digits needed, so has a clear disadvantage compared to hex or decimal.
  - vasco 2y ago
    > Hex is only better than decimal if hex allows the number of digits to be reduced. If we need to only encode 26 elements, then hex doesn't reduce the number of digits compared to decimal, so hex has no advantage over decimal in the 26-element case He had more than 26 things to encode, I believe he started with numbers, letters and a question mark. > Using just 0 or 1 will increase the number of digits needed, so has a clear disadvantage compared to hex or decimal Using 0 or 1 decreases that to only 3 cards (including question mark), and increasing the safety margin to 120° on the setup he had. It'd take longer but be more robust.
    - Thorrez 2y ago
      >He had more than 26 things to encode Ok, then hoten's comment had an error which propagated to my comments: >26 division of a circle was too much for reliable determination of which sign the camera was pointing at
shortrounddev2 2y ago
He later painstakingly translates machine code transmitted via the camera to the rover which patches the software to allow him to chat via text, so hex came in handy

unsupp0rted 2y ago

Too bad he didn't know Hangul (Korean writing system). He could have managed to communicate well enough with half a dozen chars.