--- a/ch03.roff	Fri Apr 20 19:14:30 2012 +0200
+++ b/ch03.roff	Fri Apr 20 19:14:56 2012 +0200
@@ -4,9 +4,119 @@
 .P
 bar
 
-.H1 "Removal of Old Stuff
+.H1 "Removal of Code Relicts
+.P
+The code base of mmh originates in the late 70s, had been extensively
+worked on in the mid 80s, and had been partly reorganized and extended
+in the 90s. Relicts of all those times had gathered in the code base.
+My goal was to remove any ancient code parts. One part of the task was
+converting obsolete code constructs to standard constructs, the other part
+was dropping obsolete functions.
+.P
+As I'm not even thirty years old and have no more than seven years of
+Unix experience, I needed to learn about the history in retroperspective.
+Older people likely have used those ancient constructs themself
+and have suffered from their incompatiblities and have longed for
+standardization. Unfortunately, I have only read that others had done so.
+This put me in a much more difficult positions when working on the old
+code. I needed to recherche what other would have known by heart from
+experience. All my programming experience comes from a time past ANSI C
+and past POSIX. Although I knew about the times before, I took the
+current state implicitely for granted most of the time.
+.P
+Being aware of
+these facts, I rather let people with more historic experience solve the 
+task of converting the ancient code constructs to standardized ones.
+Luckily, Lyndon Nerenberg focused on this task at the nmh project.
+He converted large parts of the code to POSIX constructs, removing
+the conditionals compilation for now standardized features.
+I'm thankful for this task being solved. I only pulled the changes into
+mmh.
+.P
+The other task of dropping ancient functionality to remove old code,
+I did myself, though. My position to strip mmh to the bare minimum of
+frequently used features is much more revolutional than the nmh community
+sees it. Without the need to justify my decisions, I was able to quickly
+remove code I considered ancient. The need to discuss my decisions with
+peers likely would have slowed this process down. Of course, I did research
+if a particular feature really should be dropped. Having not had any
+contact to this feature within my computer life was a first indicator to
+drop it, but I also asked others and searched the literature for modern
+usage of the feature. If it appeared to be truly ancient, I dropped it.
+The reason for dropping is always part of the commit message in the
+version control system. Thus, it is easy for others to check their
+view on the topic with mine and possibly to argue for reinclusion.
+
+.U2 "MMDF maildrop support
+.P
+I did drop any support for the MMDF maildrop format. This type of format
+is conceptionally similar to the mbox format, but uses four bytes with
+value 1 (\fL^A^A^A^A\fP) as message delimiter,
+instead of the string ``\fLFrom\0\fP''.
+Due to the similarity and mbox being the de-facto standard maildrop
+format on Unix, but also due to the larger influence of Sendmail than MMDF,
+the MMDF maildrop format had vanished.
 .P
-foo
+The simplifications within the code were only moderate. Switches could
+be removed from tools like
+.L packf ,
+which generate packed mailboxes. Only one packed mailbox format remained:
+mbox.
+The most important changes affect the equally named mail parsing routine in
+.L sbr/m_getfld.c .
+The direct MMDF code had been removed, but as now only one packed mailbox
+format is left, code structure simplifications are likely possible.
+The reason why they are still outstanding is the heavily optimized code
+of \fLm_getfld()\fP. Changes beyond a small local scope \(en
+which restructuring in its core is \(en cause a high risk of damaging
+the intricate workings of the optimized code. This problem is know
+to the developers of nmh, too. They also avoid touching this minefield
+if possible.
+
+.U2 "UUCP Bang Paths
+.P
+More questionably than the former topic is the removal of support for the
+UUCP bang path address style. However, the user may translate the bang
+paths on retrieval to Internet addresses and the other way on posting
+messages. The former can be done my an MDA like procmail; the latter
+by a sendmail wrapper. This would ensure that any address handling would
+work as expected. However, it might just work well without any
+such modifications, as mmh does not touch addresses much, in general.
+But I can't ensure as I have never used an environment with bang paths.
+Also, the behavior might break at any point in further development.
+
+.U2 "Hardcopy terminal support
+.P
+More of a funny anecdote is the remaining of a check for printing to a
+hardcopy terminal until Spring 2012, when I finally removed it.
+I surely would be very happy to see such a terminal in action, maybe
+actually being able to work on it, but I fear my chances are null.
+.P
+The check only prevented a pager to be placed between the outputting
+program (\fLmhl\fP) and the terminal. This could have been ensured with
+the \fL-nomoreproc\fP at the command line statically, too.
+
+.U2 "Removed support for header fields
+.P
+The `Encrypted' header had been introduced by RFC\^822, but already
+marked legacy in RFC 2822. It was superseded by FIXME.
+Mmh does no more support this header.
+.P
+`Content-MD5' headers were introduced by RFC\^1864. They provide only
+a verification of data corruption during the transfer. By no means can
+they ensure verbatim end-to-end delivery of the contents. This is clearly
+stated in the RFC. The proper approach to provide verificationability
+of content in an end-to-end relationship is the use of digital cryptography
+(RFCs FIXME). On the other hand, transfer protocols should ensure the
+integrity of the transmission. In combinations these two approaches
+make the `Content-MD5' header field useless. In consequence, I removed
+the support for it. By this removal, MD5 computation is not needed
+anywhere in mmh. Hence, over 500 lines of code were removed by this one
+change. Even if the `Content-MD5' header field is useful sometimes,
+I value its usefulnes less than the improvement in maintainability, caused
+by the removal.
+
+
 
 .H1 "Paths to ...
 .P