Discovering CS is an open-source introductory-level computer engineering online textbook, all in one handy NodeJS app!
The content of the text is arranged in a top-down fashion, starting with the high-level systems that students will have encountered in day-to-day life and then examining how these are programmed, what ISA operations they involve, what circuitry executes these ISA operations, and finally how digital logic circuitry is actually fabricated.
It includes many interactive elements, including in-browser Python and AVR ISA simulators, a binary calculator, and even a framework for online homework submission.
To get started, simply clone this repositry, navigate to the home directory, and run:
touch ratings/ratings.log
touch logs/access.log
npm install
node app.js
which will start up a server on localhost:61453
See https://github.com/daniel3735928559/run-discovering-cs for the scripts used to deploy the book in the wild.
Chapter 1 introduces the course as a whole, starting with a precise definition of what we mean by the word "computer". This will be a relatively simple notion, and the course will revolve around two separate questions:
- How can we program a computer?
- How can we build a computer?
The first question will be addressed in chapters 2–6, and the second in chapters 7–8.
Chapter 2 starts in on the study of programming. Programming occurs in two steps: When we come up against a problem, the first step is to describe a precise sequence of steps that will solve it. Such a set of steps, written in English (or human language of choice) is called an algorithm, and is the focus of section 2.2.
Once we have an algorithm, the second step is to rewrite that algorithm not in human language, but in a computer-understandable language. This will be the program. In section 2.3, we introduce a particular programming language--a simplified version of Python--to illustrate this process.
In chapter 2, we learned a simple subset of the Python programming language. Its simplicity made it easier to explain, but hard to use for any complicated or interesting tasks. Chapter 3 is devoted to expanding our knowledge of Python so we can work toward programs that actually behave like software as we know it in the real world.
Chapter 4 is a brief digression: As we descend to the level of the computer hardware, we are going to need a new language to talk about numbers as a computer understands them. This is accomplished by using binary representations for numbers, as is explained in chapter 4.
In chapters 2 and 3, we learned our first programming language. This language is not understood or used directly by the computer. Instead, the computer understands a much more basic language, called the ISA, and our programs from chapters 2 and 3 had to be translated to this basic language before being run by the computer.
To truly understand what a computer does under the hood, we need to learn to work with the ISA directly, which is the goal of chapter 5. This happens in two parts: We learn what the main components inside the computer are (that is, the computer's "architecture"), and then we learn what instructions the computer itself natively understands for manipulating these components (that is, the computer's "instruction set").
Chapter 5 is another brief but fun digression to address the question of, now that we know that the computer deals in numbers, how is it that we can manipulate things like text and images using computers as well? The answer is that everything that a computer with, from text to images to the ISA instructions themselves, must actually be numbers behind the scenes. The schemes by which numbers are made to correspond to text or to graphical data or to instructions are called encodings, and we explore several different types of encoding in this chapter.
Chapter 7 switches to the second question of "How to build a computer". Since we now understand the ISA, we can do this by taking the major tasks that the various ISA instructions need to be able to accomplish, imagining we have some black-box circuit components that perform these tasks, and examining how the circuit components can be connected to create an actual machine that accomplishes the ISA tasks--that is, a computer!
Once we have in hand a list of the circuit components we need to build a machine capable of executing ISA instructions, all that remains is to build these components. To do this, we examine in chapter 8 the building blocks of digital circuits: Logic gates and, ultimately, transistors.
Unless otherwise indicated, all work in this text is licensed under the Creative Commons Attribution, Non-Commercial, Share-Alike 4.0 International license.