TSS:

This, the first article, is the first published mention of 386BSD. By this time, the project had been operational for 18 months, and William Jolitz was at Berkeley working on the Net/2 release.
In this installment, we discussed the beginning of our project and the initial framework that guided our efforts, in particular, the development of the 386BSD specification.

Hardware context switch state description and the part where 386BSD context switching intrudes into the machine independent code semantics.

Sometimes you're forced to use processor features - like hardware context switching. Origionally, the earliest versions of 386BSD didn't use the hardware context switch TSS feature - but you still had to have one anyways.

This article, last of the original three done altogether in 1990, on getting the critical pieces functioning independantly that we needed to do the port. Once these we obtained, the kernel was inevitable.

Here's an oddity we had in the initial port. We first avoided the 386 TSS context switch because it was slow. With the 486 and later, it wasn't so we used it. But we needed at lead one to transit rings.