SCO

Why not start reading and find out?

At the time of 1rst edition, there were many more affordable processors than INTEL on the market and so the book was so you could develop an OS with what you found...
I read the book back in 1992 I think and started to studay and develop a minx on a 80286 I recuperated and on a Z80, I wanted to try on a motorola68000 I had but busted the keyboard interface... Before finishing a friend came along with a linux alpha version and I went on dual boot with that spending my nights and weekend ... And dropped my minix project. but from what I remember there might be a site that gives you hints ( and code) depending on architecture and if so it would be mentionned in the book I cant check for you as I dont know what I did with my copy...

I would suggest to start with classic. Old UNIX kernels are very easy to understand und to hack. You can find e.g. UNIX v6 or v7 on TUHS archive, Supnik's PDP-11 simulator (simh) and take Lion's Commentary on UNIX v6 source code - Lions' Commentary on UNIX 6th Edition, with Source Code. The book was long time ago a study guide for students learning Operating systems.

If you want to study a modern Unix derived from AT&T Unix code (SVR4), you might have a look to Solaris Internals: Solaris 10 and OpenSolaris Kernel Architecture . An open source branch (Illumos) is available here

thanks you all

[corona688] I'd like to design the route from the beginning so i don't like read something
then drop it and fail at the middle

[agent.kgb] can I find books and manuals and datasheet explaining both
Architecture,assembly and interface with PDP-11 ?
the book you mentioned contain code snippets only or have the complete
source code attached in an appendix or can i get it for version 6 from some
website written in C ?

thanx

There are a lot of information about PDP-11 in the Internet. It is the first computer, UNIX runs on. Just search for PDP-11 to find general information and links, and then

The book I've mentioned contains source code, but I am not sure, how full it is. UNIX v6/v7 source code is available from The Unix Heritage Society site and as a software kit to Bob Supnik's simulator Software Kits

That is often the way of things, sadly. One doesn't reach the moon with their first rocket, and we aren't still running the first UNIX circa epoch time 0.

Retracing UNIX's footsteps from the beginning as agent.kgb suggests is an interesting approach. The PDP-11 is a very primitive computer but not quite so primitive that you have to input the bootloader by toggling switches.