The cloud concept has been hot for several years. Most non-professionals only know about cloud computing, cloud storage, etc. The intuitive impression is that Tianyi Cloud, Baidu Cloud, etc. in the mobile phone, and occasionally follow the popular rhythm about big data, super computer and the like. For our supporting manufacturers, the construction of data centers such as Tencent IDC and Ali IDC may be more straightforward.
These are all appearances. It is the dazzling variety of application software that really solves the various problems you face. Maybe your company needs to get an OA system to solve the problem of office automation; or it needs an ERP system to improve the company. Efficiency of management; marketing and customer service departments need customized CRM to help them make precise attacks and win large orders.
In the past, to implement these applications, your boss would find his IT director and ask him to make a list of servers, PCs, operating systems, professional software, networks, and even professional network administrators, and figure out how to get on the system. In order to repay the investment and bring benefits to the enterprise. This is called On-Premises. If you want to run some enterprise applications on your office or company website, you need to buy servers, or other expensive hardware, and have a dedicated IT department to control local applications , to get your business up and running.
However, after the emergence of cloud computing, it may not be the same as before if you want to use such a set of applications. People who are not so professional can easily build applications that can meet their own needs according to their own needs. What's going on? Woolen cloth?
Before introducing the changes, let's first explain several conceptual names of cloud computing. According to the authoritative definition of NIST (National Institute of Standards and Technology), the service model of cloud computing has three categories or levels of SPI (ie SaaS, PaaS and IaaS).
Three levels of cloud computing
IAAS: Infrastructure-as-a-Service, with IAAS, you can outsource the hardware elsewhere. The service provided by IAAS to consumers is the utilization of all computing infrastructure, including processing CPU, memory, storage, network and other basic computing resources, users can deploy and run arbitrary software, including operating systems and applications. The consumer does not manage or control any cloud computing infrastructure, but can control the choice of operating system, storage space, deployed applications, and may also gain control of limited network components (such as routers, firewalls, load balancers, etc.) .
PaaS: Platform-as-a-Service (Platform as a Service), is the so-called PAAS, sometimes called middleware. It is to deploy the application developed or acquired by the customer using the provided development language and tools (such as Java, python, .Net, etc.) to the supplier's cloud computing infrastructure. The customer does not need to manage or control the underlying cloud infrastructure, including networks, servers, operating systems, storage, etc., but the customer has control over the deployed applications and possibly the configuration of the hosting environment in which the applications run
SaaS: Software-as-a-Service (software as a service), also known as SAAS. The services that SAAS provides to customers are applications running on cloud computing infrastructure that users can access through a client interface, such as a browser, on various devices. Consumers do not need to manage or control any cloud computing infrastructure, including networks, servers, operating systems, storage, and more;
Differences and connections between SAAS, PAAS and IAAS
IAAS will provide off-site server, storage and networking hardware that you can rent.
Save on maintenance costs and office space, companies can utilize the hardware to run their applications at any time. The IAAS service we are most familiar with is our server hosting business. Most IDCs provide such services. Users do not want to purchase expensive servers and disk arrays. All hardware is provided by IAAS, and you can also get better quality high network resources.PAAS provides various solutions for developing and distributing applications online , such as virtual servers and specific operating systems.
3/4 of the underlying platform has been built for you, you only need to develop your own upper-level applications. This not only saves your cost on hardware, but also makes the development of various applications more convenient, and it becomes easier for different tasks to communicate with each other, because the same programming language, protocol and underlying code are followed on the same platform. Many web applications, application web hosting, storage, security and application development collaboration tools. The most familiar PAAS platforms are Baidu BAE, Sina SAE, Ali, Tencent Cloud and so on. Many e-commerce platforms, video websites, etc. can be quickly deployed through PAAS.SAAS与我们普通使用者联系可能是最直接的，简单地说任何一个远程服务器上的应用都可以通过网络来运行，就是SAAS了。
我们最容易接触到的是挂在网页或微信上的各类小程序，比如H5的应用如火如荼，这些应用给了IT的门外汉实现自己愿望的机会。国内的互联网巨头竭力推介的SAAS应用想必大家已经耳熟能详了，比如阿里的钉钉，腾讯的企业微信，这些软件里面应用平台上的可供使用的各类SAAS小软件数不胜数，从OA，到ERP到CRM等等，涵盖了企业运行所需的几乎所用应用。
最后，拿做批萨这件事来举例说明本地部署和SPI的差别吧，相信大家一看就懂了！
On-Premises（本地部署）：在家自己做，面粉等原材料也自己买，自己发酵，自己加工！
IAAS（基础设施即服务）：厨房是自己的，批萨的原料买的是半成品，面粉供应商已经发酵好了，调味也帮你弄好了，你只需要进烘箱烤就行了！
PaaS（平台即服务）：打电话叫外卖将披萨送到家中，自己只需要准备桌子和餐具。
SaaS（软件即服务）：直接去披萨店吃披萨，你带张嘴就可以了（当然还有钱）
批萨就是我们想使用的服务（或曰软件或曰应用），对于到处拔草的你，习惯了饿了吗的你，你会发现在云时代，我们的工作也可以象拔草和外卖那样轻松解决了！
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