I learned octal before hex. The Univac 1100/80 was my first machine. It was 36 bit words, and had circuitry to process multiple data sizes; 6, 9, 12, 18 bit. Octal made perfect sense.
>FIXED-POINT OPERANDS: One 36-bit single precision
word. Addition and subtraction can also be performed upon
2-word (72-bit) double precision operands and upon 18-bit
half-words and 12-bit third-words; the leftmost bit holds the
sign in each case. Moreover, partial words of 6,9, 12, or 18
bits can be transferred into and out of the arithmetic and
control registers. The 11 00/80 can also perform decimal
addition and subtraction operations on 9-bit bytes, packed 4
to a word.
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