OK, if you don't have any real experience in low-level embedded coding (relevant to device drivers), RTOS or OS design in general, file systems, data structures, algorithms, interfaces, etc. And, if you have "hobby level" experience with Assembler, C and C++. And, if your intent is to write a desktop OS, from the ground up, without making use of existing technologies, drivers, file systems, memory management, POSIX, etc. Here's a list of books that could be considered required reading before you can really start to write specifications and code. Pick twenty of these and that might be a good start.

In no particular order:

1- http://www.amazon.com/C-Programming-Language-2nd-Edition/dp/...

2- http://www.amazon.com/The-Answer-Book-Solutions-Programming/...

3- http://www.amazon.com/The-Standard-Library-P-J-Plauger/dp/01...

4- http://www.amazon.com/C-Traps-Pitfalls-Andrew-Koenig/dp/0201...

5- http://www.amazon.com/Expert-Programming-Peter-van-Linden/dp...

6- http://www.amazon.com/Data-Structures-In-Noel-Kalicharan/dp/...

7- http://www.amazon.com/Data-Structures-Using-Aaron-Tenenbaum/...

8- http://www.amazon.com/Mastering-Algorithms-C-Kyle-Loudon/dp/...

9- http://www.amazon.com/Code-Complete-Practical-Handbook-Const...

10- http://www.amazon.com/Design-Patterns-Elements-Reusable-Obje...

11- http://www.amazon.com/The-Mythical-Man-Month-Engineering-Ann...

12- http://www.amazon.com/The-Programming-Language-4th-Edition/d...

13- http://www.amazon.com/The-Standard-Library-Tutorial-Referenc...

14- http://www.amazon.com/API-Design-C-Martin-Reddy/dp/012385003...

15- http://www.amazon.com/The-Linux-Programming-Interface-Handbo...

16- http://www.amazon.com/Computer-Systems-Programmers-Perspecti...

17- http://www.amazon.com/System-Programming-Unix-Adam-Hoover/dp...

18- http://www.amazon.com/Memory-Programming-Concept-Frantisek-F...

19- http://www.amazon.com/Memory-Management-Implementations-Prog...

20- http://www.amazon.com/UNIX-Filesystems-Evolution-Design-Impl...

21- http://www.amazon.com/PCI-System-Architecture-4th-Edition/dp...

22- http://www.amazon.com/Universal-Serial-System-Architecture-E...

23- http://www.amazon.com/Introduction-PCI-Express-Hardware-Deve...

24- http://www.amazon.com/Serial-Storage-Architecture-Applicatio...

25- http://www.amazon.com/SATA-Storage-Technology-Serial-ATA/dp/...

26- http://www.amazon.com/Beyond-BIOS-Developing-Extensible-Inte...

27- http://www.amazon.com/Professional-Assembly-Language-Program...

28- http://www.amazon.com/Linux-Kernel-Development-3rd-Edition/d...

29- http://www.amazon.com/Version-Control-Git-collaborative-deve...

30- http://www.amazon.com/Embedded-Software-Primer-David-Simon/d...

31- http://www.amazon.com/Programming-Embedded-Systems-C/dp/1565...

32- http://www.amazon.com/Making-Embedded-Systems-Patterns-Softw...

33- http://www.amazon.com/Operating-System-Concepts-Abraham-Silb...

34- http://www.amazon.com/Performance-Preemptive-Multitasking-Mi...

35- http://www.amazon.com/Design-Operating-System-Prentice-Hall-...

36- http://www.amazon.com/Unix-Network-Programming-Sockets-Netwo...

37- http://www.amazon.com/TCP-Illustrated-Volume-Addison-Wesley-...

38- http://www.amazon.com/TCP-IP-Illustrated-Vol-Implementation/...

39- http://www.amazon.com/TCP-Illustrated-Vol-Transactions-Proto...

40- http://www.amazon.com/User-Interface-Design-Programmers-Spol...

41- http://www.amazon.com/Designing-Interfaces-Jenifer-Tidwell/d...

42- http://www.amazon.com/Designing-Interfaces-Jenifer-Tidwell/d...

43- http://www.amazon.com/Programming-POSIX-Threads-David-Butenh...

44- http://www.intel.com/p/en_US/embedded/hwsw/software/hd-gma#d...

45- http://www.intel.com/content/www/us/en/processors/architectu...

46- http://www.intel.com/p/en_US/embedded/hwsw/hardware/core-b75...

47- http://www.hdmi.org/index.aspx

48- http://en.wikipedia.org/wiki/Digital_Visual_Interface

49- http://www.amazon.com/Essential-Device-Drivers-Sreekrishnan-...

50- http://www.amazon.com/Making-Embedded-Systems-Patterns-Softw...

51- http://www.amazon.com/Python-Programming-Introduction-Comput...

52- http://www.amazon.com/Practical-System-Design-Dominic-Giampa...

53- http://www.amazon.com/File-Systems-Structures-Thomas-Harbron...

54- ...well, I'll stop here.

Of course, the equivalent knowledge can be obtained by trial-and-error, which would take longer and might result in costly errors and imperfect design. The greater danger here is that a sole developer, without the feedback and interaction of even a small group of capable and experienced programmers could simply burn a lot of time repeating the mistakes made by those who have already trenched that territory.

If the goal is to write a small RTOS on a small but nicely-featured microcontroller, then the C books and the uC/OS book might be a good shove in the right direction. Things start getting complicated if you need to write such things as a full USB stack, PCIe subsystem, graphics drivers, etc.