OCR A Level Computer Science (H446)Specification point 1.4.1

OCR H446 1.4.1: Data Types

The free BugBot lessons that teach this point, a robot to try it on, and the past-paper questions that test it.

Lessons that teach it

  1. A7.1 Number sets, bases and units Data representation
    Natural, integer, rational, irrational, real and ordinal numbers; any number base; bits, bytes, kilo and kibi.
  2. A7.2 Binary arithmetic and signed integers Data representation
    Unsigned addition and multiplication, sign and magnitude, two's complement, subtraction and overflow.
  3. A7.3 Fixed point and floating point Data representation
    Binary fractions, mantissa and exponent, normalisation, and adding floating point numbers.
  4. A7.4 Errors, range and precision Data representation
    Rounding errors, absolute and relative error, range against precision, overflow and underflow, with a real sensor reading.
  5. A7.5 Bitwise operations and characters Data representation
    Masks with AND, OR and XOR, logical, arithmetic and circular shifts, and characters as codes in ASCII and Unicode.
  6. A7.10 Project: a secure sensor packet Data representation
    Pack a distance reading into fixed point bytes with flags and a checksum, encrypt it with a one-time pad and send it by radio.
  7. A15.7 Calculation and theory questions Exam preparation
    Number representation, floating point, Boolean logic, state machines and complexity answered quickly and checked.

Try it on a robot

The task from A7.1 Number sets, bases and units, running here. Change the program and press Run.

The specification is OCR's own document; this page says which of our lessons teach point 1.4.1 and is not endorsed by the board.