Hi everyone, welcome to the first chapter in our Tencent Cloud Developer Associate Course. Essentials of Cloud Development. At the end of this chapter, you'll be able to understand the characteristics of traditional businesses. The traditional application development modes, the basic concept of cloud computing, and the business characteristics and development modes in the cloud era. In this chapter, we'll cover two sections. Traditional application development and cloud application development. This video will cover the first section, traditional application development. The next video will cover the second section. Okay, let's get started with Section 1, traditional application development. In this video, we'll cover the characteristics of traditional IT architecture, business-driven IT architecture transformation, and challenges brought by Internet Plus. First, let's go over some of the characteristics of Traditional IT Architecture. Traditional enterprise IT construction consists of the OA, ERP, CRM, student archive management systems, asset management systems, and more. The characteristics of traditional IT architecture include clear requirements, a small user base, slow iterative upgrades, low technical complexity, and slow requirement changes. The traditional application development mode consists of a software development mode based on the waterfall model with standardization, clear stages, and correlation. Additionally, the software architecture is monolithic, featuring fast development and low costs. The waterfall model was the earliest software development model proposed by Winston W Royce in 1970. A fixed sequence is given and the development lifecycle transitions from the previous phase to the next stage step by step until the release and delivery of the deployed software product. Which is just like flowing water in a waterfall. The definition phase consists of planning and requirement analysis. The development phase consists of design, coding, and testing. The maintenance phase consists of Ops. A monolithic architecture is the simplest software architecture often used in traditional application software development and traditional web applications. For example, an ecommerce platform implemented in a general architecture consists of multiple individual projects for features such as login, permission control, membership, inventory, order, favoring, following, and cart. As the project-based businesses become increasingly complex and more and more developers are involved, the corresponding capabilities of development, compilation, deployment, technical upgrades, and horizontal scaling will all be restricted. Some of the challenges brought by business development include difficult communication between applications developed in different languages. Data silos, poor code reusability, larger user bases, high server pressure, and more. IT architecture supports business growth through hardware infrastructure. As the number of users increases, the scale of server clusters also needs to expand to respond quickly to business changes. And the requirements for hardware infrastructure construction will also increase. For software architecture, the traditional monolithic application architecture creates a high number of information silos. Making it difficult to interconnect between software programs across business departments and reuse code. Therefore, a new architecture is required to improve the status quo. For self-built data centers and cluster scaling, the enterprise undertakes all the work in the data center on its own. This includes planning and construction, deployment, Ops, business system deployment, security ops, availability, and reliability. Which naturally come with high costs. Traditional internet data centers or IDCs are divided into two types, physical server hosting and rental. Physical server hosting is when a user purchases hardware devices on their own and sends them to a hosting service provider's IDC for hosting. During the hosting period, the monitoring and management of the devices are performed independently by the user while the IDC provides IP access, bandwidth access, power supply, and network maintenance. For rentals, the IDC rents physical devices to the user and is responsible for the stability of the environments. As a result, the user does not need to purchase devices. Some of the changes in software architecture includes service-oriented architecture or SOA. The SOA-based architecture idea extracts repetitive and common features into components and provides them to various systems in the form of services. Enterprise service bus or ESB acts as a communications bridge between projects and services. Okay, let's look at some of the challenges brought by Internet Plus. The different business characteristics of the Internet Plus era include a large user base and diversified access methods, centralized access and traffic surges, big data, ever changing market requirements, and more. The challenges of Internet Plus also include the limitations of traditional infrastructure. Server devices and data centers require high upfront investments and maintenance by dedicated personnel. Resources also need to be deployed redundantly, leading to low utilization and waste. Additionally, systems cannot tackle traffic surges efficiently and flexibly. In order to overcome these challenges, we must find a solution that can achieve pay-as-you-go billing and auto scaling, reduce costs, and maintain elasticity.