Understanding computing
In computer science, computing refers to the activities that computers perform in order to communicate, manage, and process information. Computing is usually divided into four main areas: algorithms, architecture, programming languages, and theory.
Since, we've discussed theory and algorithms in previous sections, we will now focus on defining architecture and programming languages.
Architecture
Computer architecture refers to the set of instructions that interact with computer systems. In more basic terms, the architecture includes the instructions that allow software and hardware to interact. Computer architecture has three main subcategories: Instruction Set Architecture (ISA), Microarchitecture, and System Design.
Instruction Set Architecture (ISA)
The ISA is the boundary that exists between the hardware and the software. It is classified in multiple ways, but two common ones are complex instruction set computer (CISC) and reduced instruction set computer (RISC). These are defined as follows:
- CISC: This is a computer that has explicit instructions for many tasks, such as simple mathematical operations, and loading something from memory. CISC includes everything that is not included in RISC.
- RISC: This is a computer with an architecture that has reduced cycles per instruction (CPI).
CISC tries to complete instructions with fewer steps, while RISC only uses simple instructions. CISC is multi-step, while RISC is single-step, performing one task at a time. The CISC process includes the instructions, the microcode conversion, microinstructions, and execution. By contrast, RISC includes instructions and execution.
In CISC, microcode conversion refers to the interpretation of the language at a lower level. It takes into consideration the hardware resources to create microinstructions. Microinstructions are single instructions in microcode. After microcode creates the microinstructions, the microinstructions can be executed. The following diagram shows the process for both RISC and CISC:
Figure 1.8 – Difference between RISC and CISC
Both RISC and CISC are necessary for computer programmers. There are advantages and disadvantages to having a single-step process (RISC) versus a multi-step process (CISC). RISC reduces the cycles per instruction, doing one thing at a time. CISC reduces the instructions in a program, but at the cost of cycles per instruction. Depending on what our needs are, we can choose the best path to take.
Programming languages
Programming languages are the way we write instructions for computers and other devices. Different languages are used depending on what is needed, ease of use, and much more. Examples of programming languages include the following:
- Ruby and Python: Ruby is a programming language mostly used for web applications. Ruby is stable and easy to use; however, many developers choose to use Python over Ruby because Python is faster. Although Ruby has not been as popular and had some performance issues, the language is very much alive in 2019 and continues to grow. Python, on the other hand, is widely used for multiple purposes, such as web applications, user interface applications, and websites, among others. We will explore Python in greater depth later on in this book.
- C: The C languages are a critically important part of computer science, as C was the first language used and is still the most widely used language. C has been around since 1972, when Dennis Ritchie invented it, but it has been used by others since 1978, when it was first published. While other languages have grown in popularity since, C is still used in 2019. Some of its uses include operating systems, hardware drivers, and applications, among others. C is a base-level language, which means it requires almost no abstraction.
- C++: C++ was developed by Bjarne Stroustrup as an extension of C in 1985. The goal of the language was to add object-oriented capabilities. The language is still widely used both in conjunction with the C language in operating systems and for other software. C++ is an intermediate-level programming language.
- C#: C# (C sharp) is a high-level programming language. Much like C++, it has object-oriented capabilities and is an extension of the C programming language. One of the main differences between C++ and C# is that C++ uses machine code while C# uses bytecode. Machine code can be executed directly by a computer. Bytecode has to be compiled, so it is considered a low-level code that needs to be interpreted.
- Swift: The Swift programming language was developed by Apple Inc. in 2014. As programming languages go, Swift is one of the newest. Apple released it as an open source programming language with version 2.2, which was released in 2015. The language is considered to be a general-purpose and compiled programming language.
- Scratch: Scratch was developed as a visual programming, block-coding language in 2002 by MIT Media Lab. As a block programming language, it is used extensively in schools to teach students of all ages how to code. Scratch is now adapted for multiple uses, including some robotic applications, such as Vex Code, incorporating machine learning and artificial intelligence, and much more. It is compatible with popular classroom peripherals such as the Makey Makey, which is a circuit that interacts with the computer and can be fully controlled with a Scratch program. While it is popular for educational purposes, the power of the programming language cannot be understated and the language itself and its functionalities continue to grow.
- Java and JavaScript: JavaScript is a scripting language that is used only within browsers. It is used in the making of websites and web applications. Java, on the other hand, is a general-purpose programming language. JavaScript helps us make websites animated or add interactive functionalities to them. Contrastingly, Java is compiled into bytecode and is widely used in the development of Android devices and applications.
- PHP: PHP is otherwise known as Hypertext Preprocessor. Much like Java, it is a general-purpose programming language. It is widely available, as it is open source. PHP is used in website design and applications and is considered to be easy to learn, yet has many advanced features. PHP can also be used to write desktop applications.
- SQL: SQL, or structured query language, is a programming language used to interact with data. SQL is domain-specific. It has been around for almost as long as C, making its first appearance in 1974. The main importance of SQL is that it can interact with databases, where other languages are not able to do so.
In computational thinking, we use many different programming languages, depending on what our goals are, what information we have or need, and what our application or software requirements are. Choosing a language is dependent on not just our knowledge of the language, but the possible functionalities of the language.
We will get to work more extensively with Python in this book because of its open source nature, ease of use, and the large number of applications it can be used for. However, Python is not the only option. Knowing about other languages is important, especially for developers.
In this section, we learned about computing and a few of its areas, namely, architecture and programming languages. We also learned about the ISA and its types, along with an introduction to various programming languages. In the next section, we'll look at data types and structures.