How should I learn PHP, C, and Linux?

Php Chinese network (www.php.cn) provides the most comprehensive basic tutorial on programming technology, introducing HTML, CSS, Javascript, Python, Java, Ruby, C, PHP, basic knowledge of MySQL and other programming languages. At the same time, this site also provides a large number of online instances, through which you can better learn programming... Reply: problem-driven. PHP has the same (or similar) library function definition as C. These are basically the packaging of C library functions. In addition, if it is developed under LAMP, you may encounter various problems. if you dig deep into these problems, you will learn a lot of underlying knowledge. after a long time, you can easily write C. of course, if you develop it under LAMP, you will naturally learn Linux-related knowledge passively. everything is so refined and silent: I have seen many people talking about the bottom layer, but no one has ever said what the bottom layer is. The bottom layer is a huge piece of things. we can even refer to what we don't see as the bottom layer.

What is the underlying layer that you refer to when learning PHP, C, or Linux and then going to the underlying layer?

If it is php or c, does it mean the code compilation process, how does php perform garbage collection, and how does stack space be allocated?

In Linux, does the kernel mean the underlying layer or the driver? Whether it is about operating system scheduling, disk file management, or network I/O control.

In the same opinion as @, you will learn a lot of underlying knowledge when you dig deep into and think about the problems you encounter. Wang Guowei divided his learning into three realms. we should first grasp the overall direction, namely, "Last night, the West Wind withered green trees, the tall buildings, and the sky and the roads", and then "The clothes are getting wider and never regret, ". Then, the so-called bottom layer is something that comes naturally. as your experience and experience gradually accumulate. This problem is not accurate, because for the network front-end, Linux is the underlying layer; for Linux, the driver layer is the underlying layer, but for the driver layer, FPGA and CPLD are the underlying layers, so what do you want to learn?
We recommend that you use LZ to clarify the entire system structure and study it based on your needs. Otherwise, it would be nice to have a fight between the East and the West...

What do you want to do at the bottom? For Embedded Development, write an operating system, or write a language? We should learn object-oriented learning through PHP first.