I am an L&S CS major. Why do I have to take this class? So you don’t look stupid when you get to your job. To prepare you for hands-on courses like CS 150 that involve hardware design. Because it’s good to know the physical basis of computation.

Digital Information All information inside a computer is represented numerically. Text: Every letter is represented by a number (ASCII code). Images: A bitmap image is a table of numbers, with each entry representing the color of a pixel. { = 123 Row 3, Column 2 = 00FF44

Number Representation There are many ways to represent numbers. Decimal (base 10, the usual way) Hexadecimal (base 16, often used in the study of computers) Binary (base 2) The ability to represent any number in binary, using 0’s and 1’s, makes computation as we know it possible.

High and Low Logic Levels The numbers 0 and 1 are represented by physical quantities: The number 0 (called logic 0) is represented with a voltage near 0 V. The number 1 (called logic 1) is represented with a voltage between 2 and 5 V, depending on the technology. Circuits perform computation by taking voltage inputs and allowing current to flow, creating voltage outputs.

A Logic Gate The mathematical operation known as “AND” is performed by this circuit: A B S S S S V DD D S D S A B

Course Content To analyze the circuits that perform computation, you need to know about Circuit analysis: voltages and currents so you can see how circuits work, resistance and capacitance so you see how long it takes to compute something Electronics: transistors which make complex computation feasible

Devices We will look inside Memories: DRAM, latches, flip-flops… A/D and D/A Converters Logic Gates and more!