/joh'liks/ n.,adj. 386BSD

Porting Unix to the 386: A Practical Approach



William & Lynne Jolitz


The 386BSD specification was in two parts - one that detailed getting to a operational system that could build itself and basic console applications, and a more extensive community involvement part, called "A Modest Proposal".




Development of the 386BSD Specification


Once all the materials were gathered, the temptation was to immediately sit at the PC and write code. This is a temptation that should always be vigorously avoided. One needs to sit down and carefully break down this project into smaller bites. However, because many parts of this project are interrelated, we must insure that the internal standards are uniformly maintained by all areas of the port and during all phases. In other words, the bridge must meet in the center.

Therefore, instead of plunging directly into development, we began the most critical phase of this (or any) port -- that of creating the 386BSD specification. This specification addressed the following major issues:

  • Segmentation and paging
  • Virtual and physical address space
  • Process context description
  • System call interfaces
  • ISA device requirements
  • Microprocessor idiosyncrasies
  • Bootstrap
Unlike a commercial specification, the 386BSD specification was intended to be lightweight and flexible. We wanted to focus 386BSD without making the specification a major work in itself. We also knew that many of the finer points would change as we got closer to our goal.



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Copyright 1989, 1990, 2006 TeleMuse Partners, William Jolitz and Lynne Jolitz