3 ms·
I love that there's a fractal world down there; from that the digits 0-9 start with bit pattern 0011 and then their value in binary to make easy convertion to/f
by jodrellblank 4y ago
I love that there's a fractal world down there; from that the digits 0-9 start with bit pattern 0011 and then their value in binary to make easy convertion to/from BCD, and that control codes Start Message and End Message were positioned to maximise the Hamming distance so they're maximally different and least likely to be misinterpreted as each other in case of bits being mixed up, that 7-bit ASCII used on 8-bit tape drives left room for a parity bit for each character, that lowercase and uppercase letters differ only by the toggling of a single bit, that some of the digit/shift-symbol pairings date back to the first typewriter with a shift key in 1878...
- jasomill 4y agoAnd my personal favorite: DEL is 1111111 so it could be punched over any other character to "delete" it from a paper tape.
- IIAOPSW 4y agoIn the 8 bit variant you could also interpret it as the Morse Code letter ........, which is an early form of non-printable character known as a "procedure sign" (aka "pro-sign"), and is often transcribed as letters without the inter-letter spacing (Eg <SOS> is the transcription of ...---...). The prosign <eeeeeeee> means the sender has mis-keyed something and you should ignore the previous character.