Release notes for Nachos 4.0.

Nachos 4.0 is somewhat of a re-write of Nachos 3.4. The main differences are:

1. better software engineering -- every class has its own selftest routines,

2. the system is sligthly more portable (it was developed on an Alpha, and ported to DOS by a student)

3. uses templates for generic data structures

4. reconfiguring for different machines is more obvious

5. somewhat different assignments (you can find these off the Web page, alas they were done in Word, so they can't be easily edited)

6. the major downside is that it is no longer in synch with Narten's roadmap (see web page)

My recommendation is that people currently using 3.4 shouldn't bother to use 4.0, unless they need to run on a 64 bit machine or DOS. Even those new to Nachos will find Narten's roadmap probably outweighs the benefits of using 4.0, except if they need DOS or Alpha support.