








                       C News vs. VMS


                       Henry Spencer

                      Dept. of Zoology
                   University of Toronto





     To run C News at all, you need a fairly good  emulation
of Unix.  There are several such for VMS.  They have various
minor imperfections.  The only one we specifically  _k_n_o_w  of
that  is  a real problem for C News is the inability to make
real links for cross-postings.  There is  some  half-hearted
code  in  various places that tries to deal with this situa-
tion.  It has _n_o_t been tested too thoroughly.

     _R_e_l_a_y_n_e_w_s normally files an  article  under  its  first
group  and  then  makes  hard links into further groups.  If
_r_e_l_a_y_n_e_w_s finds itself unable to make a hard link,  it  will
try making a symbolic link instead.  The one situation where
this will fall down is if a news article's header  is  enor-
mous,  too  big  to  fit  in  core.  In this case, _r_e_l_a_y_n_e_w_s
stores the article in a temporary file, makes  links  to  it
under  all  the appropriate names, and then unlinks the tem-
porary name.  This obviously isn't  going  to  work  if  the
appropriate-name  links  are symbolic.  We believe this case
essentially never happens on  large-address-space  machines,
and is quite rare even for small address spaces.

     _E_x_p_i_r_e has a -l option that tells it  to  consider  the
first  name  of  an  article  as  the  ``leader'', not to be
deleted until all others have been deleted.

     The one place where extra work would be necessary would
be  _m_k_h_i_s_t_o_r_y,  which has no notion that some links are dif-
ferent from others.

     So far as we know, we don't get into any of  the  other
trouble  areas  of  Unix emulation on VMS, at least with the
Eunice emulator.  We don't have a VMS handy for testing,  so
we make no guarantees.









                       27 May 1989


