Error correction

• For $p$ parity bits, need $2^p$ spaces—very efficient for large $p$.

Encoding

• Unary
• One-Hot
• Standard binary
• Gray coding

Some methods are easier to correct, some are more efficient

Boolean Algebra

Primary connectives:

Identity, Negation, AND, OR

Secondary connectives:

XOR, XNOR (equivalence, $\bar A B + A\bar B$), implication ($\bar A + B$)

NAND, NOR

Physical Realization

Cost

2 transistors NOT

n-input NAND/NOR $2\cdot n$ transistors

Properties of Gates

• Closure