I was fascinated by computers right from the moment I got an opportunity to lay my hands on one. I learned BASIC programming in school when I was in grade eight. Those were the days of the 80286 with BASICA on MS-DOS. I went on to complete my degree in Medicine. After completion my interest in computers returned as I got the opportunity of developing a small database system for the hospital I was working. I went on to learn C++, Visual Basic, and ultimately Assembler. I always had a fantasy of developing my own operating system and started reading more and more about that. I ultimately set down to develop a small operating system, which will help me understand the PC better. I then realised the difficulties I underwent to get the needed help and so decided to write the OS as a tutorial as well. I am not sure if the OS will ultimately be completed. But I am sure the reader will be able to complete his/her own version as he/she works with it. Developing the system (which is still under process) was great fun and I am sure the reader will enjoy developing his/her own system.
A basic/working knowledge of Assembler with an unrelenting desire to explore and know more and to develop something new will be needed to start the project. My own knowledge of the PC is derived from books ('Under the IBM PC' by Peter Norton is an excellent text and I would suggest readers to get a copy of it and read it cover to cover) as a result of which the project will be very much limited in expertise. A copy of the excellent and free NASM (Netwide assembler) is needed for developing the system. You can download your free copy at NASM. All development is done on the Windows operating system. It is also possible to do the same under Unix/Linux system. Differences will be hinted whenever needed.
JOSH, as I named it to signify a sense of excitement/satisfaction, will be a real-mode operating system to make learning faster and easier (and my own understanding of the protected mode has only just started). Like MS-DOS it will be interrupt driven. JOSH will be a single tasking operating system.