Porting Unix to the 386: A Practical Approach

William & Lynne Jolitz

Started open source UNIX.

Appeared in part as a 17 article magazine series in 1991-1992.

Documented the "how, what, why, who, when" of porting BSD to the 386.

Done while BSD was becoming "open source".

Porting Unix to the 386: A Practical Approach - prototype kernel

prototype kernel:

Extending the Standalone System

Booting a kernel didn't require all of this - but by extending support, we had a "mini kernel" like functionality. Dillemma - how much do you let the boostrap/loader actually do? We chose after the kernel was up to have it to the most - but this answer is subject to review.

Processor Support -- i386.c

We initialized the processor with initial descriptor and page tables - one needs to run with the tables before activating memory/interrupt kernel functions.

Where Do We Go From Here?

We had put the plan of the first article into action, used the second articles tools to load test programs as the kernel, extending standalone operation. This created a base for the kernel and user environment.

Porting Unix to the 386: Language Tools Cross Support

We describe the need and use of a cross-support environment to create 386 code from a non-386 machine, so as to create the initial binarys before our port can generate them.