Open University Department of Computer Science

This is a condensed summary of the learning content and does not cover the content of all subjects. (Considering copyright) Instead, it is mainly written based on additional research, so details other than the course flow may differ.

Cloud Computing

Cloud computing is a concept that emerged in 1996 and refers to a form of computing that provides both characteristics by combining the meaning of a cloud that can easily change its form and properties and the meaning of the various processing functions of a computer. It has become popular as an alternative to the existing on-premise method to reduce construction costs and increase efficiency by utilizing idle servers. And it is growing steadily due to the combination of individual, corporate, and government-led policies regarding cloud computing technology.

• On-Premise
• A method of owning and operating the data center required to provide information services
• Cloud computing has led to a shift from on-premises capital expenditures to operational expenditures.

SLA (Service Level Agreement)

A service quality guarantee contract that stipulates that the cloud service provider that rents IT resources quantifies and clearly presents the level of service provided to users and compensates for damages if it falls short.

How to use cloud computing

IaaS is suitable for users or organizations that want to directly control the infrastructure, while PaaS is suitable for users or organizations that want to focus on application development. IaaS

• This service provides infrastructure, including virtual servers, storage, and networks.
• Representative examples include AWS EC2, Microsoft Azure, etc. PaaS
• This is a platform service that provides an environment for application development and deployment.
• Representative examples include Heroku, Google App Engine, and Cafe24. SaaS
• This is a service that provides software, allowing you to use the software through a web browser.
• Representative examples include Google Drive and Dropbox.

Cloud computing deployment model

Public / Private / Hybrid / Multi / Community Cloud What is the difference between hybrid cloud and multi-cloud? Hybrid cloud is the use of a combination of your own data centers and public clouds, while multi-cloud is the use of services from multiple cloud providers. Hybrid clouds are used to reduce costs in public clouds while protecting sensitive data in your own data centers. This allows Company A to use a more flexible infrastructure in the public cloud while keeping sensitive data safe. Multi-cloud uses services from multiple cloud providers, such as AWS and Azure, to build multiple clouds. This allows Company B to deliver high availability and performance by taking advantage of the advantages offered by each cloud provider. For example, AWS provides services for machine learning, and Azure provides services for Windows applications. By utilizing the services provided by each cloud provider, Company B can utilize a variety of functions and technologies.

Cloud computing technology

Clustering technology / Grid computing technology / Virtualization technology / Serverless computing technology

• Grid computing technology
• This is a technology that uses multiple distributed computers as one virtual supercomputer.
• Technology in which computing resources are registered as a logical resource pool on the platform and the resources included in the pool collectively provide a high-performance computing environment
• Resource connectivity is very small, and resources of different types are physically distributed.
• Differences from clustering techniques that act like a single system
• Serverless computing technology
• Instead of building or managing servers yourself, this is a technology where a cloud service provider manages servers and pays for what you use. That doesn't mean there are no servers.

Netflix Cloud Computing Application Cases

I came across the Netflix tech blog after you mentioned it in class, and there was a lot of interesting content, so I'll organize it and post it later. :) streaming

• Netflix has signed an agreement with AWS (Amazon Web Services) to provide stable streaming services to numerous users around the world. AWS provides the infrastructure Netflix needs, allowing Netflix to provide high levels of availability and performance to its users. Personalized Recommendations
• Netflix uses a custom recommendation algorithm hosted on AWS to provide personalized content recommendations to users. This makes it easier for users to find new shows and movies they might like. Large-scale data processing
• Netflix uses a variety of data processing tools from AWS to perform large-scale data processing. This allows Netflix to release new shows and movies faster and gives users more choices.

Compiler configuration

Compiler Configuration Basic Concepts

assembler

• It is a translator that translates programs written in assembly language into machine language. Basically, it is responsible for converting low-level language into machine language. compiler
• It is a translator that translates programs written in high-level languages (BASIC, JAVA, C, C++, etc.) into low-level languages (assembly language or machine language). Because the compiler is executed after translation, execution speed is fast, but it requires a large memory space. preprocessor
• It serves to extend the programming language by adding useful features to it. Both the source language and the target language are composed of high-level languages. interpreter
• Receives high-level language input, executes it simultaneously with translation, and outputs the results. It is mainly used when implementing conversational languages. Although it has a long execution time, it allows flexible conversation with the user. Program language processing process
• Lexical analysis: Recognizes operators, identifiers, reserved words, delimiters, constants, etc. and separates them into tokens.
• Parse: Outputs the analysis results as parstry and creates a syntax tree.
• Semantic analysis: When performing mixed operations, change integers to real numbers. It gives meaning to the pastry and generates intermediate code through preliminary work before execution. Afterwards, it goes through an optimization process.
• Object code generation: Generates the final code.

Finite Automata

It is a mathematical model of a system that accepts special things in strings made from a certain alphabet. The main types are non-deterministic finite automata (NFA) and deterministic finite automata (DFA).

Chomsky hierarchy

Formal grammar is divided into four types according to the type of production rule. There are grammars from Type 0 to Type 3, and each type represents a grammar with specific restrictions.