I thinks this 1,000 OS book is a good start for beginners before diving into the MINIX book.

MINIX book describes more practical designs, with a more feature-rich implementation. However, UNIX features such fork, brk, and tty are not intuitive for beginners. By writing a toy OS first, readers can compare the toy OS with MINIX, and understand that UNIX-like is just one of many possible designs. That's an important perspective IMO.

Also, readers can actually implement better algorithms described in the MINIX book. It makes the MINIX book more interesting to read.