The circular diagram is to illustrate ring architecture, its not representing physical media, but how different layer of software interact from the most privilegied at the center, like the kernel who has all access to everything, to least privilegied like user application on the outer layer, whose access is restricted at ring boundaries.
For programs stored on media like cd or dvd, programs are just regular data, as long as the kernel can mount the filesystem, and read the data from the different files stored on it, it can load the code and other files from it, and execute them.
I'll probably make another post to explain basics of unix C programing, file and network access, and executable file as well as libraries latter to explain better the ring architecture.
But the ring structure is not especially related to physical location of the data, the kernel can decide arbitrarily using cpu memory unit which pages of memory can be accessed by a process.
thanks. i rely want undestand how a program run in a disc or tape running
Basically the kernel load the exe from the filesystem to memory and create a process out of it.
Exe file contain different sections, at least one code section and a data section, as well as an exported entry point which tell the loader where the code start inside of the code section.
The kernel loads each sections in memory, and resolve reference to the data used by the code, and insert the program in the process table.
But ill make a more in depth post for this.