[9fans] another version of the kernel notes

[9fans] another version of the kernel notes

[nemo]

You can download it from the same urls I gave before.
Forgive me for the errors yet to be fixed, and feel free
to suggest any kind of thing (reordering, fixes, using a
different approach to explain the code, adding things,
removing things, etc.)

regards



Since the last version of the document, these things have been fixed.
     * Starting up chapter:
          + Small section about PC hardware added.
          + Horrendous bug about how do QIDs work fixed (I said that vers
            was used to detect removed-and-recreated files, which is not
            the case; In fact I think I understood that was not the case
            long ago before starting this document. Too sleepy that day?
            Too few caffeine? Who knows?).

            I already wrote 1000 times how QIDs work, (thanks rc), so
            I have paid my mistake.

          + pageinit has nothing to do with software for paging, it is
            just initializing the page allocator. The starting up chapter
            was saying it had to do with software MMU, although on the
            next paragraphs it was described and the reader could know
            what it really does.
          + psstate only holds the process state for ps.
          + process groups have name spaces, not processes. The
            description was confussing.
     * Process chapter:
          + Note added about why to use a scheduler stack.
          + Note added about why to have two scheduling classes.
          + Note added about other synch. means.
          + postnote fix.
          + Note for wakeup in pexit.
          + procstopwait fix.
     * Files chapter: not yet fixed, but for...
          + Note added about why to have a limit on file descriptors.
     * Memory chapter: not yet fixed.