What ultimately matters in this course is not so much where you end up relative to your classmates but where you end up relative to yourself when you began

  • When you’re learning something new, don’t compare yourself to others. Instead, focus on what you’ve learned through the learning process.

  • What does computer science actually do?

    • Computer science is the study of information.

    • To understand how to represent information in a computer.

    • Problem solving

What does it actually mean to solve a problem?

We can view a problem as an input and our goal as an output. To solve the problem, we provide a model that takes the input and generates the output. The model is the way we solve the problem.

What is an algorithm?

Algorithms can be viewed as a series of steps used to solve problems. When we identify certain steps that can solve a problem, we can teach these steps to computers or other human beings. These problem-solving steps are what we call algorithms. So, if you’re afraid to learn algorithms like I was, just think of it as teaching a computer how to solve problem LOL.

Main numeral system

  • Unary (base-1)

    • example: counting numbers using our fingers.

  • Binary (base-2)

    • What is currently used in computer system.

  • decimal (base-10)

    • What is commonly used by people.

Why are computers using a base-2 system?

Computers just simplify things a little bit,because computers, at the end of the day,only have access to electricity, on or off.They don’t have access to 10 different types of electricity, just 2.

Electricity can only represent two states, so computers use binary. if we can find a technology that can stably represent ten states, perhaps computers could use a decimal system. Then, technology will be have improved significantly.

How do we represent characters in a computer?

We use a mapping system to teach computers how to represent characters. ASCII and Unicode are commonly used in almost all computers. For example, in ASCII, 1000001 represents A, and 0110000 represents 0.

What is the difference between ASCII and Unicode?

ASCII and Unicode are similar in that they are both mapping systems designed to teach computers how to represent characters. While ASCII can represent only 127 characters, Unicode can represent a lot more characters.

How does computers represent an image?

In a simple way, we use certain bytes to represent color (RGB) and certain byrtes to represent location. If you have ever downloaded images from the internet or taken pictures on your phone, you maybe familiar with file extensions like .jpg and .jpeg. The computers can tell difference patterns to use reading the binary data with different file extension.

For example, you can see the green pass sign in Taiwan. The sign is made up of many small colored dots that combine to form an image.