架构和云计算

HarmonyOS

• About HarmonyOS

Hardware

• 芯片和 ISA 指令集；
• The Multikernel: A new OS architecture for scalable multicore systems：22nd Symposium on Operating Systems Principles | October 2009。Three design principles:
  (1) make all inter-core communication explicit,
  (2) make OS structure hardware-neutral, and
  (3) view state as replicated instead of shared.
  The multikernel model
• Distributed operating system
  Single system image：microkernel，management components collection.
  The MINIX 3 microkernel, for example, has only approximately 12,000 lines of code. An Introduction to MINIX 对 MINIX 来龙去脉讲得清楚。
  Structure of monolithic and microkernel-based operating systems, respectively
  image.png

— A kernel is a program which runs after the bootloader and is in control of everything after it. It manages various services as input and output management, handling various call made to the system known as system calls, etc. It resides on the low-level of abstraction. Also, it acts as an interface/bridge between the operating system and central processing unit.
　A microkernel is a software or a program in which user services and kernel services are present in different address space. Due to which the size of the microkernel becomes smaller than that of a monolithic kernel. But as the user services and kernel services are in different address space in order for a user service to use a kernel service, message passing was used. This makes the execution of microkernel to be slower.
　The microkernel is easily extendible. Due to which if a new service has to be added then it would not require any changes to the kernel itself. Also, if any user service crashes it doesn’t affect the working of the microkernel.

Cloud computing

amorphous cloud

The group of networked elements providing services need not be individually addressed or managed by users; instead, the entire provider-managed suite of hardware and software can be thought of as an amorphous cloud.

CDN

Content delivery network

• CDN：地理位置分布，流量、带宽、存储。
• 云计算：按需获取、按量付费、即付即用，主要是数据存储和计算能力。数字时代的基础设施和智能引擎。借助强大弹性和高可扩展性以最大化实现IT资源的规模效应。计算资源的廉价提供。

Computer performance

• short response time
• high throughput
• low utilization of computing resources
• high availability
• high bandwith
• short data transmission time

Google Cloud Platform

GCP