IaaS指提供系统（可以自己选）或者储存空间之类的硬件，软件要自己手动装；PaaS提供语言环境和框架（可以自己选）；SaaS只能使用开发好的软件（卖软件本身）；BaaS一般类似于非关系数据库，但各家不通用，有时还有一些其它东西。

• https://education.github.com/pack GitHub学生包，需用教育邮箱验证。各种福利，可从DigitalOcean上手
• https://github.com/ripienaar/free-for-dev 本文尽量不与此项目重复
• https://free.zhelper.net/
• https://github.com/AchoArnold/discount-for-student-dev

• In open Ubuntu 18.04 machine click Parallels Actions -> "Install Parallels Tools"

• A "Parallels Tools" CD will popup on your Ubuntu desktop.

• Open it by double mouse click, copy all the content to a new, empty directory on a desktop, name it for e.g. "parallels_fixed"

• Open terminal, change directory to parallels_fixed (cd ~/Desktop/parallels_fixed)

• Make command line installer executable (chmod +x install)

• Change directory to "installer" (cd installer)

• Make few other scripts executable: chmod +x installer.* *.sh prl_*