I just read one chapter, which I thought was OK. It felt more like a book on how the C programming language translates to operating system concepts, rather than a book about the operating system concepts themselves. For example, the chapter I read discusses malloc() and indicates that it allocates memory from the heap, but it doesn't mention sbrk().

It often splits practical vs. theoretical concepts. One chapter might go over the theoretical scheduling algorithms, and then another might address practical solutions to internal fragmentation.

Disclaimer: I'm definitely not an expert, I'm reading the book to learn.

These days sbrk is rarely used, in fact, on Apple systems I am under the impression that it is depracated (A quick search confirms this impression).

The correct approach is to use mmap with the MAP_ANON flag (Which interestingly isn't doesn't seem to be fully documented in the Linux documentation...)