In order  to replace some  assembler and  REXX code with  portable PASCAL
code, a number of changes to list caching have been made in version 1.8a.
These changes  also bring  very significant performance  improvements for
large  lists,  especially  in  terms  of I/O,  for  the  list  management
functions that  are now  written in PASCAL  (ADD, SUBSCRIBE,  QUERY, SET,
etc). For  instance, a  QUIET ADD  to a 5000-users  list only  results in
about 10  I/O operations rather than  300 (as usual, only  the second and
subsequent  operations  after  a   reboot  benefit  from  this  caching).
Functions implemented in REXX that do their  own I/O to the LIST files do
not, unfortunately, benefit from these improvements.
 
As a  result of these  changes, a  number of unsupported  list management
practices  that used  to  work in  previous versions  will  no longer  be
available.
 
Unsupported practices that continue to work as before:
 
- Editing  the LIST  file manually  (with  XEDIT) while  LISTSERV is  not
  running.
 
- Deleting  one or  more subscribers  from a  LIST file  via XEDIT  while
  LISTSERV is running.
 
- Changing the  name (but  not the  address) of  one or  more subscribers
  while LISTSERV is running.
 
- Removing blank lines from the LIST file while LISTSERV is running.
 
Unsupported practices that will no longer work:
 
- Adding new  subscribers via XEDIT  while LISTSERV is  running: LISTSERV
  may later claim that the new subscribers  are not on the list. The same
  applies to changes made to a subscriber's address.
 
- Altering list header keywords via  XEDIT while LISTSERV is running: the
  changes will not be picked up.
 
- Using the 'listname CACHE' files as a means to obtain information about
  list header  keywords: LISTSERV no  longer creates these files,  and as
  before the only supported mechanism  for extracting list keywords is to
  use the LSVKEYWD  function, which is a  supported permanent programming
  interface.
 
A temporary programming  interface has been provided for  cases where you
absolutely need to modify LIST files via external programs while LISTSERV
is running.  You should make  the changes as you  used to and,  after the
last change  is made and the  file has been closed,  but before returning
control to LISTSERV, do:
 
                        Call LSVFSI 'HR',listname
 
You could place this instruction in  your PROFILE XEDIT, for instance. If
you specify '*' for the list name, all lists are affected at once.
 
  Eric