Question 1

What is octal numbering?

Accepted Answer

Octal is base-8 numbering using digits 0–7. It was commonly used in early computing because 3 binary bits map exactly to one octal digit (000=0, 111=7). While largely replaced by hexadecimal, octal remains in use for Unix file permissions (e.g. chmod 755).

Question 2

How is a character converted to octal?

Accepted Answer

Take the character's ASCII or Unicode code point (decimal), then convert to base-8. 'A' = 65 decimal = 101 octal. 'a' = 97 decimal = 141 octal. Each character typically uses 3 octal digits.

Question 3

Where is octal still used today?

Accepted Answer

Primarily in Unix/Linux file permissions: rwxr-xr-x = 755 in octal (4+2+1, 4+0+1, 4+0+1). Network protocols, some legacy systems, and assembly programming occasionally use octal notation. For most modern applications, hexadecimal is preferred.

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