Comprehensive Overview of Cloud Computing: Definitions, Features, Service Models, Deployment Types, History, and Market Landscape

Definition Cloud computing refers to the delivery of computing resources—such as servers, storage, databases, networking, software, and analytics—over the Internet by cloud providers on a pay‑as‑you‑go basis, enabling elastic, shared infrastructure for users.

Main Features a) Elastic scalability – resources can be increased or decreased on demand. b) Low cost – no need to purchase hardware or bear maintenance labor. c) Fast provisioning – services are available with a click. d) Improved efficiency – businesses focus on core activities while the provider manages the underlying hardware. e) Performance and scale – global data centers reduce latency. f) Strong reliability – redundancy, backup, disaster recovery, and business continuity.

Classification by Service Type

IaaS – provides fundamental IT infrastructure (servers, VMs, storage, networking, OS).

PaaS – offers development, testing, delivery, and management environments without the need to manage underlying infrastructure.

SaaS – delivers software applications and user interfaces on a subscription basis.

Classification by Deployment Type

Public cloud – third‑party providers deliver services; users pay only for what they use.

Private cloud – operated by a single organization, either on‑premise or hosted.

Hybrid cloud – combines public and private clouds, sharing responsibilities between the enterprise and the provider.

Community cloud – shared by organizations with common interests, policies, or compliance requirements.

Development History

1. Stage 1 (1960s): Mainframe era, high reliability and performance but costly and inflexible. 2. Stage 2 (1980s): PC‑based servers and networking emerged, offering lower cost but still limited scalability. 3. Stage 3 (1998): VMware introduced virtualization, improving resource utilization. 4. Stage 4 (2006): Amazon launched Elastic Compute Cloud (EC2), providing on‑demand, elastic IT resources.

US vs. China Cloud Computing Development

In the United States, early investment by giants such as Amazon and Google accelerated adoption, leading to a mature ecosystem where public and private clouds serve enterprises, governments, and the broader public. China lagged 5‑7 years, initially learning from abroad, but strong government support sparked rapid growth from 2017 onward.

Business Models and Characteristics

Shared resources – network, servers, storage, applications, and services are pooled.

On‑demand and scalable – pay‑per‑use with minimal management overhead.

From product to service – users rent hardware and software instead of purchasing them.

License‑to‑service transition – providers offer subscription or usage‑based pricing.

Scale‑driven competitive barriers – larger customer bases lower costs and increase stickiness.

IaaS Competitive Landscape

Globally, AWS dominates with a market share three times larger than the next four providers combined. In China, Alibaba Cloud holds >80% of the IaaS market, followed by Tencent Cloud, Kingsoft Cloud, China Telecom, and UCloud (together ~68%).

PaaS Competitive Landscape

Globally, Salesforce and AWS lead the public‑cloud PaaS market. In China, Alibaba Cloud leads with ~27% share; foreign vendors such as Oracle, AWS, and IBM compete through partnerships with local players.

SaaS Competitive Landscape

Worldwide, Salesforce holds 11% of SaaS revenue, followed by Microsoft (8%) and Adobe (6%). In China, Kingdee, Oracle, and Microsoft each capture roughly 5‑7% of the market, with SaaS offerings split between generic (CRM, OA, HR) and vertical solutions.

Key Players

Amazon Web Services (AWS) – launched in 2006; offers S3, EC2, SQS, SimpleDB, and commands the largest global market share.

Microsoft Azure – founded as Windows Azure in 2008, rebranded in 2014; provides a broad portfolio (Azure platform, Office 365, Dynamics 365) and operates in 42 regions.

Salesforce – pioneer of SaaS and CRM, founded 1999; delivers Sales Cloud, Service Cloud, Platform Cloud, and AppExchange with a subscription model.

Summary

Cloud computing is a capital‑intensive, technology‑intensive industry where economies of scale drive cost reductions and market concentration. Major players are typically internet giants (Amazon, Google) or established software firms (Microsoft). Their flagship applications (e.g., Office) fuel cloud adoption, creating a mature and evolving ecosystem.