List "digests" are provided
for those users who prefer to receive (typically) one large, comprehensive
posting per digest period that includes all of the list traffic
from that period, rather than receiving each post individually
as processed by the server.
If "Notebook= Yes...", the
digest feature defaults to daily digests cut at midnight with
the "work" files kept in the same directory as the list's
notebook archives. If "Notebook= No", digests are not enabled by
default. However, note that lists without notebook archives can
have digests; it is simply necessary to enable digests manually
for such lists by using the "Digest=" list header keyword and
specifying a valid path for the location of the digest's work
files.
Digests can be set up to cut
on a Daily, Weekly, or Monthly basis, and can be further configured
to cut after a certain number of lines of data have been stored
regardless of the digest period setting. This ability to
generate "special issues" when the digest reaches a certain size
may be necessary if people complain that your 10,000 line daily
digest is getting truncated by their mail host to 1500 (or even
1000) lines.
For example, if a high volume
list is set for Daily digests, and the "Size(nnn)" parameter of
the "Digest=" keyword for the list is set to "Size(1000)", a
"special issue" of the digest will be cut and mailed to digest
subscribers whenever the listname.DIGEST file reaches 1000 lines
of text. Note that LISTSERV will not cut the digest at exactly
1000 lines, thereby truncating the last message; LISTSERV will
cut the digest after the end of the message that causes the
digest file to go over its limit. Thus, if the digest file is
950 lines long and a 200 line message is received, the "special
issue" digest will be 1150 lines long.