UNIX spell system: several questions

[R. P. C. Rodgers]

Dear Netlandic Wizards,

I climb to your hermit's cave to ask a question about the UNIX spell
system.  As distributed with "classical" BSD, the directory /usr/dict
contains the files/directories:

  hlista (hash list of American spellings)
  hlistb (hash list of British spellings)
  words  (presumably words used to create hash list of American spellings)
  hstop  (hash list of stop words)
  papers (not relevant here)

Present understandings (I welcome corrections if these are in error):

1) hstop, the hash table for the stop list, contains words which would
   normally be passed as correct by spell, but in fact are misspellings.

2) spellin is essentially identical to spell in function except that the
   stop list is not employed.

Questions:

1) Is "words" truly the list of words used to create hlista?  Can one exactly
   reproduce hlists by using spellin with the file "words" as input?

2) Can someone better explain the function and use of the -x option
   ("every plausible stem is printed with '=' for each word").

And now for the biggy:

3) Where is the list of stop words used to create hstop?  We have been
   patiently collecting additions to the spelling dictionary for years, and
   find that there are some correctly spelled words which appear in the stop
   list.  Without the original list of stop words, it would appear impossible
   to repair this problem.

The spell man page goes down in my book as one of the most poorly written in
the UNIX canon.

Thanks in advance for any enlightenment,

Rick Rodgers
R. P. C. Rodgers, M.D.         (415)476-8910 (work) 664-0560 (home)
UCSF Laurel Heights Campus     UUCP: ...ucbvax.berkeley.edu!cca.ucsf.edu!rodgers
3333 California St., Suite 102 ARPA: rodgers at maxwell.mmwb.ucsf.edu
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