--- a/ch03.roff	Fri Jun 01 12:42:52 2012 +0200
+++ b/ch03.roff	Fri Jun 01 15:33:37 2012 +0200
@@ -9,8 +9,6 @@
 
 .H1 "Stream-lining
 
-
-.H2 "Removal of non-MUA Tools
 .P
 MH had been considered an all-in-one system for mail handling.
 The community around nmh has a similar understanding.
@@ -31,6 +29,120 @@
 available resources should be concentrated at the point where MH is
 most unique. This is clearly the MUA part.
 .P
+The goal for mmh was to remove peripheral parts and stream-line
+it for the MUA task.
+
+
+.H2 "Removal of Mail Transfer Facilities
+.P
+In contrast to nmh, which also provides mail submission and mail retrieval
+facilities, mmh is a MUA only.
+.P
+The MSA is called ``Message Transfer Service'' (MTS) in nmh.
+The facility establishes TCP/IP connections and speaks SMTP to submit
+messages for relay to the outside world.
+This part is implemented in the
+.Pn post
+command.
+Demanded by the changes in
+emailing, this part of nmh required changes in the last years.
+Encrypted connections needed to be supported, hence SASL was introduced
+into nmh. This added complexity to the nmh without improving it in
+its core functions. Also, keeping up with recent developments in
+this field needs requires development power and specialists.
+Mmh cuts this whole facility off and depends on an external MTA instead.
+The only outgoing interface available to mmh is the
+.Pn sendmail
+command.
+Almost any MTA provides a
+.Pn sendmail
+command.
+It not, any program can be substituted if it reads the
+message from the standard input, extracts the recipient addresses
+from the message header and does not conflict
+with sendmail-specific command line arguments.
+.P
+To retrieve mail, the
+.Pn inc
+command in nmh has the ability to establish TCP/IP connections
+and speaks POP3 to retrieve mail from remote servers.
+As with mail submission, here encrypted connections are required
+today, thus SASL support was added.
+As POP3 is superseded by IMAP more and more, support for message
+retrieval through IMAP will become necessary to be added soon.
+Mmh has no support for retrieving mail from remote locations.
+It depends on an external tool to cover this task.
+There are two ways for messages to enter mmh's mail storage:
+Incorporate them with
+.Pn inc
+from the system maildrop, or with
+.Pn rcvstore
+from the standard input.
+.P
+In consequence, mmh includes neither networking nor SASL code anymore.
+Two large separate functional units are removed.
+They account for about XXX lines of code and XXX libraries.
+.P
+With the removal of the MSA and MRA, mmh converted from an all-in-one
+mail system to the core: the MUA.
+Following the Unix philosophy, it focuses on one job and to do that well.
+Now, of course, mmh depends on third-party software.
+An external MTA/MSA is required to transfer mail to the outside world;
+an external MRA is required to retrieve mail from remote machines.
+There exist excellent implementations of such software,
+which do this specific task likely much better than the internal
+versions of nmh do it. Also, this provides the choice for the best
+suiting one of the available implementation.
+.P
+As it had already been possible to use an external MSA or MRA,
+why not keep the internal version for convenience?
+If this would question the sense in having a fall-back pager in all
+the command line tools, in case
+.Pn more
+or
+.Pn less
+wouldn't be available, the answer is intuitively seen.
+Now, an MSA or MRA is clearly more complex than a text pager, but
+still the concept holds: If programs become complex, split them;
+if projects become complex, split them.
+Complexity is demanded by the problem to solve. Decades ago,
+emailing had been small and simple.
+(Remember,
+.Pn /bin/mail
+had once covered anything there was to email.)
+As the complexity in emailing increased, MH remainded mostly unchanged.
+Nontheless, in nmh the POP server, which the original MH had included,
+was removed. Now is the time to take one step further and remove
+the MSA and MRA.
+Not only does it decrease the code amount of the project,
+but more important, it removes the whole field of message transfer
+with all its implications from the project.
+.P
+Users of MH are usually able to set up an external MSA and MRA.
+Also, the popular MSAs and MRAs have large communities and a lot
+of documentation available.
+.P
+Choices for MSAs range from the full-featured
+.I Postfix
+over mid-size solutions like
+.I masqmail
+and
+.I dma
+to small forwarders like
+.I ssmtp
+and
+.I nullmailer .
+Choices for MRAs include
+.I fetchmail ,
+.I getmail ,
+.I mpop
+and
+.I fdm .
+
+
+
+.H2 "Removal of non-MUA Tools
+.P
 Several of nmh's tools were removed from mmh because they didn't
 match the main focus of adding to the MUA's task.
 .P
@@ -99,9 +211,6 @@
 .Pn wmh ,
 saved more than 7\|000 lines of C code \(en a major achievement.
 
-.U2 "Removal of the MTS
-.P
-
 
 .H2 "mhshow show Merge
 .P