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Rework and new text about mmh's name in the Intro.
author markus schnalke <meillo@marmaro.de>
date Wed, 16 May 2012 17:40:34 +0200
parents 22ae3981a76b
children c21ff903c71c
rev   line source
meillo@39 1 .RN 1
meillo@39 2
meillo@0 3 .H0 "Introduction
meillo@0 4 .P
meillo@32 5 This chapter introduces MH, its history, concepts and how it is used.
meillo@32 6 Then, it describes nmh's code base and community to give the reader
meillo@32 7 a better understanding of the state from which mmh started off.
meillo@32 8 Further more, this chapter lists the motivation and goals of the mmh project.
meillo@32 9 This chapter introduces MH, nmh and mmh to the reader and outlines
meillo@32 10 the mmh project itself.
meillo@8 11
meillo@0 12
meillo@28 13 .H1 "MH \(en the Mail Handler
meillo@0 14 .P
meillo@2 15 MH is an electronic mail system, originating in the RAND Corporation.
meillo@32 16 Most important for this thesis is that MH defines a mail handling concept.
meillo@32 17 In fact, MH had started as a design proposal, not as an implementation,
meillo@32 18 and in spirit it had remained this way. This is similar to Unix, which
meillo@42 19 influenced the world more in being a set of system design concepts
meillo@32 20 than in being a specific software product.
meillo@42 21 These ideas behind Unix are summarized in the \fIUnix philosophy\fP.
meillo@42 22 MH follows this philosophy.
meillo@2 23
meillo@11 24 .U2 "History
meillo@2 25 .P
meillo@2 26 MH is an electronic mail system, originating in the RAND Corporation.
meillo@32 27 In 1977 at RAND Corporation, Norman Shapiro and Stockton Gaines
meillo@32 28 had proposed the design
meillo@32 29 of a new mail handling system, called ``Mail Handler'' (MH),
meillo@32 30 to superseed RAND's old monolithic ``Mail System'' (MS).
meillo@27 31 Two years later, in 1979, Bruce Borden took the proposal and implemented a
meillo@32 32 prototype of MH.
meillo@32 33 Before the prototype had been available, the concept was
meillo@32 34 believed to be practically unusable because of being too slow.
meillo@32 35 But the prototype proved successful and replaced MS thereafter.
meillo@32 36 In replacing MS, MH became an all-in-one mail system.
meillo@2 37 .P
meillo@32 38 A decade later, the University of California at Irvine had started to use MH.
meillo@2 39 They also took over its development and pushed MH forward.
meillo@32 40 This was the time when the Internet appeared, UCB implemented
meillo@32 41 the TCP/IP stack, and Allman wrote Sendmail.
meillo@32 42 MH was extended as emailing got more features.
meillo@32 43 The development of MH was closely related to the development of email
meillo@32 44 RFCs. In the advent of MIME, MH was the first implementation of this new
meillo@32 45 email standard.
meillo@2 46 .P
meillo@2 47 In the nineties, MH had been moved into the public domain, making it
meillo@32 48 attractive to Free Software developers.
meillo@32 49 The Internet had started to become popular and in 1997,
meillo@32 50 Richard Coleman initiated the ``New Mail Handler'' (nmh) project,
meillo@32 51 a fork of MH, based on the \fILBL changes\fP by Van Jacobson, Mike Karels
meillo@32 52 and Craig Leres.
meillo@32 53 Colman intended to modernize MH and improve its portability and
meillo@32 54 MIME handling capabilities.
meillo@32 55 This should be done openly within the Internet community.
meillo@32 56 The development of MH stopped soon after the development of nmh had started.
meillo@32 57 Today, nmh almost completely replaced the original MH.
meillo@0 58
meillo@11 59 .U2 "Concepts
meillo@0 60 .P
meillo@8 61 MH is a toolchest, modelled after the Unix toolchest. It consists of a
meillo@42 62 set of tools, each covering a specific task of email handling.
meillo@42 63 The programs
meillo@8 64 operate on a common mail storage. The specific format of the mail storage
meillo@32 65 characterizes MH in the same way like the format of the file system
meillo@32 66 characterizes Unix.
meillo@42 67 .P
meillo@32 68 The mail storage consists of \fImail folders\fP (directories) and
meillo@32 69 \fPmessages\fP (regular files).
meillo@32 70 Each message is stored in a separate file in the format it had been
meillo@32 71 received (i.e. transfer format). The files are named with ascending numbers
meillo@32 72 in each folder.
meillo@42 73 .P
meillo@32 74 MH tools maintain a \fIcontext\fP, which includes
meillo@32 75 the current mail folder and current message.
meillo@32 76 Processes in Unix have a similar context, containing the current working
meillo@32 77 directory, for instance. In contrast, the process context is maintained
meillo@32 78 by the Unix kernel automatically, whereas MH tools need to maintain the MH
meillo@32 79 context themselves.
meillo@32 80 The user can have one MH context or multiple ones, he can even share it
meillo@32 81 with other users.
meillo@42 82 .P
meillo@32 83 Messages can have symbolic names. These can be automatically updated
meillo@32 84 position names like being the next or the last message,
meillo@32 85 or user-settable group names for arbitrary sets of messages.
meillo@32 86 These names are called sequences.
meillo@32 87 Sequences can be bound to the folder or to the context.
meillo@2 88 .P
meillo@32 89 New MH tools are built out of or on top of existing ones easily \(en
meillo@32 90 a property common to toolchests.
meillo@32 91 Multiple versions of the same command with different default values
meillo@32 92 are created very easily. This provides shortcuts and tayloring.
meillo@32 93 Form templates for new messages or for replies are easily exchangable.
meillo@32 94 Generally, output is adjustable with format files.
meillo@42 95 .P
meillo@32 96 The configuration is stored in a file that is called the user's \fIprofile\fP.
meillo@32 97 MH encourages the user to taylor and automate the mail handling.
meillo@42 98 Almost every part of the system can be adjusted to personal preference.
meillo@32 99 The system is well scriptable and extendable.
meillo@32 100 As the MH toolchest was modelled after the Unix toolchest, the
meillo@32 101 properties of the latter apply to the former as well.
meillo@8 102
meillo@32 103 .U2 "Versions
meillo@27 104 .P
meillo@27 105 Three versions of MH are available today:
meillo@32 106 .IP "Old MH"
meillo@42 107 .br
meillo@32 108 In most cases this version had been replaced by nmh,
meillo@32 109 but some systems might still provide old MH.
meillo@32 110 The main reasons to still use old MH are historical reasons.
meillo@32 111 MH provides hardly any benefits over nmh.
meillo@27 112 The development of old MH has stopped after the 6.8.4 release in
meillo@27 113 February 1996.
meillo@42 114 .IP nmh
meillo@42 115 .br
meillo@27 116 The most widespread version of MH was forked off version 6.8.3 in December
meillo@32 117 1996. It is based on the \fILBL changes\fP.
meillo@32 118 Backward-compatibility to old MH is provided by having new featues deactivated
meillo@32 119 by default. In consequence, the user needs to activate them explicitely to
meillo@32 120 be able to use them.
meillo@32 121 Throughout the previous years, the work on nmh was mostly maintenance work.
meillo@32 122 Development revived in December 2011 and stayed busy since then.
meillo@32 123 .IP mmh
meillo@42 124 .br
meillo@32 125 This descendent of nmh is the subject of this thesis.
meillo@32 126 It had started as an experimental version, but became de facto a fork.
meillo@8 127
meillo@27 128 .U2 "Example Session
meillo@27 129 .P
meillo@32 130 Following is an example mail handling session with mmh.
meillo@32 131 It should be mostly compatible with nmh and old MH.
meillo@32 132 Details might vary but the look'n'feel is the same.
meillo@42 133 .DS
meillo@42 134 $ \f(CBinc\fP
meillo@42 135 Incorporating new mail into inbox...
meillo@42 136
meillo@42 137 1+ 2012-05-16 11:16 meillo@dream.home Hello
meillo@42 138 2 2012-05-16 11:17 meillo@dream.home book
meillo@42 139
meillo@42 140 $ \f(CBshow\fP
meillo@42 141 Date: Wed, 16 May 2012 11:16:00 +0200
meillo@42 142 To: meillo
meillo@42 143 From: <meillo@dream.home.schnalke.org>
meillo@42 144 Subject: Hello
meillo@42 145
meillo@42 146 part text/plain 13
meillo@42 147 mmh is great
meillo@42 148
meillo@42 149 $ \f(CBnext\fP
meillo@42 150 Date: Wed, 16 May 2012 11:17:24 +0200
meillo@42 151 To: meillo
meillo@42 152 From: <meillo@dream.home.schnalke.org>
meillo@42 153 Subject: book
meillo@42 154
meillo@42 155 part text/plain 79
meillo@42 156 Hello meillo,
meillo@42 157
meillo@42 158 have a look at the ``Daemon book''. You need to read that!
meillo@42 159
meillo@42 160 foo
meillo@42 161
meillo@42 162 $ \f(CBrmm 1\fP
meillo@42 163
meillo@42 164 $ \f(CBscan\fP
meillo@42 165 2+ 2012-05-16 11:17 meillo@dream.home book
meillo@42 166
meillo@42 167 $
meillo@42 168 .DE
meillo@27 169
meillo@27 170
meillo@28 171 .H1 "nmh: Code and Community
meillo@2 172 .P
meillo@8 173 In order to understand the state, goals and dynamics of a project,
meillo@42 174 one needs to know its history. MH predates the Internet,
meillo@42 175 it comes from times before networking was universal,
meillo@42 176 times when emailing was small, short and simple.
meillo@42 177 Then it grew, spread and adopted to the changes email went through.
meillo@42 178 The core-concepts, however, remained the same.
meillo@42 179 During the 80s a small group of students at the University of
meillo@8 180 California, actively worked on MH. They added features and optimized,
meillo@8 181 like it is common for scientific work. This is still in pre-ANSI C
meillo@8 182 times. The source code contains many ancient parts. Code constructs
meillo@8 183 specific to BSD or hardware of that time are usual.
meillo@2 184 .P
meillo@8 185 Nmh started eight years after the ANSI C standard had been
meillo@8 186 established. A more modern coding style entered the code base. Still
meillo@8 187 a part of the developers come from ``the old days''. The developer
meillo@42 188 base became more diverse and thus the code had different style.
meillo@42 189 Programming practices
meillo@8 190 from different decades merged into the project. Different coding
meillo@8 191 styles came together. It appears as if multiple peers added code
meillo@42 192 parts, resulting in a conclomeration rather than a homogenic
meillo@8 193 of-one-cast mail system. Still, the basic concepts hold it together.
meillo@8 194 They were mostly untouched throughout the years.
meillo@8 195 .P
meillo@8 196 Although, at the surface, nmh is a toolchest, meaning a collection
meillo@8 197 of completely modularized small programs, on the source code level,
meillo@8 198 it is much more interweaved. Parts of the basic functions are
meillo@8 199 collected in a MH standard library, which is good, but often
meillo@8 200 separate functions are compiled into programs, for effiency reasons.
meillo@8 201 This lead to intricate innards.
meillo@8 202 The advent of MIME rose the complexity of email by a magnitude. This
meillo@8 203 is visible in nmh. The MIME-related parts are the most complex ones.
meillo@8 204 It's also visible that MIME support had been added on top of the
meillo@32 205 old MH later. The MH style made this easily possible, but it
meillo@8 206 also lead to duplicated functions (e.g. \fLshow\fP, \fLmhshow\fP)
meillo@8 207 and had not been thoroughly included into the concepts (e.g. the
meillo@8 208 user-visible access to whole messages and MIME parts are inherently
meillo@8 209 different).
meillo@8 210 .P
meillo@8 211 For compatibility's sake, it is a common understanding to have the
meillo@8 212 default settings to be compatible, requiring any new feature to be
meillo@8 213 explicitely enabled. This puts a burden on new users, because nmh
meillo@8 214 out-of-the-box keeps staying in the same ancient style, where users
meillo@8 215 usually want to have it practical for modern emailing.
meillo@8 216 But of course, this depends on if nmh is seen to be a front-end or a
meillo@8 217 back-end.
meillo@8 218
meillo@8 219
meillo@27 220 .H1 "mmh
meillo@28 221 .P
meillo@42 222 I started to work on my experimental version in Fall 2011.
meillo@42 223 In December, when I announced my work on the nmh-workers mailing list,
meillo@42 224 .[
meillo@42 225 nmh-workers mmh announce december
meillo@42 226 .]
meillo@42 227 the activity in nmh rose heavily.
meillo@42 228 Suddently the community started to move.
meillo@42 229 This movement was pushed much by Paul Vixie's ``edginess'' message.
meillo@42 230 .[
meillo@42 231 nmh-workers vixie edginess
meillo@42 232 .]
meillo@42 233 After long years of much stagnation, nmh became actively developed again.
meillo@42 234 Hence, while I was working on mmh, the community was working on nmh,
meillo@42 235 in parallel.
meillo@42 236
meillo@42 237 .U2 "Naming
meillo@28 238 .P
meillo@42 239 The name \fImmh\fP stands for \fImeillo's mail handler\fP,
meillo@42 240 because mmh is my own version of MH.
meillo@42 241 (My login name is \fImeillo\fP.)
meillo@42 242 The project follows my personal considerations and preferences.
meillo@42 243 By calling it a personal project, I don't need to justify my decisions,
meillo@42 244 though, still I do.
meillo@42 245 This enabled me to follow my vision staightly and thus produce
meillo@42 246 a result of greater pureness.
meillo@42 247 This project model was inspired by the window manager \fIdwm\fP,
meillo@42 248 which is Anselm Garbe's personal window manager \(en
meillo@42 249 targeted to satisfy Garbe's personal needs whenever conflicts appear.
meillo@42 250 dwm had remained much more focused on its original goals,
meillo@42 251 whereas its community-driven predecessor \fIwmii\fP had
meillo@42 252 grown large and lost it's leanness.
meillo@42 253 This should not happen to mmh.
meillo@42 254 .P
meillo@42 255 mmh can also stand for \fImodern mail handler\fP, and this is
meillo@42 256 the variant chosen as titel for this document. One main focus of the
meillo@42 257 project was to modernize nmh. Another main goal is resembled in the
meillo@42 258 name \fIminimized mail handler\fP: Drop any parts that don't add
meillo@42 259 to the main task of mmh, being a MUA.
meillo@42 260 .P
meillo@42 261 It should also be noted that \fLstrcmp("mmh","nmh")<0\fP is true.
meillo@42 262 Although mmh bases on nmh, it is likely seen as a step backward.
meillo@42 263 I agree.
meillo@42 264 However, this step backward actually is a step forward,
meillo@42 265 although in another direction.
meillo@27 266
meillo@27 267 .U2 "Motivation
meillo@27 268 .P
meillo@27 269 XXX
meillo@27 270
meillo@27 271 .U2 "Why it is worth it
meillo@27 272 .P
meillo@27 273 XXX
meillo@42 274 XXX comparision to monolithic mail systems.
meillo@42 275 XXX Differenciation of MUA and mail system.
meillo@27 276
meillo@27 277 .U2 "Target Field
meillo@27 278 .P
meillo@27 279 XXX Target field and scenarios
meillo@27 280 .P
meillo@27 281 The target user in mind likes Unix and its philosophy.
meillo@27 282 He likes to use programs that are conceptionally appealing.
meillo@27 283 He's familiar with the command line and enjoys its power.
meillo@27 284 He is at least capable of shell scripting and wants to improve his
meillo@27 285 productivity by scripting the mail system.
meillo@27 286 His computer and operating system are from post-ANSI C times.
meillo@27 287 He likes to attach files, exchanges text containing non-ASCII
meillo@27 288 characters, signs or encrypts his messages.
meillo@27 289 He does not use bulletin boards anymore, nor non-mbox style mail
meillo@27 290 drops, nor does he rely on compatibility to nmh.
meillo@27 291 He already has and MTA/MSA and MRA running or is able to set them
meillo@27 292 up.
meillo@27 293 He does not want to have to read a book in order to make his MUA
meillo@27 294 usable.
meillo@27 295 .P
meillo@27 296 XXX Limitations
meillo@27 297
meillo@27 298 .U2 "The Vision
meillo@8 299 .P
meillo@8 300 The general goals of the mmh project are the following:
meillo@8 301 .BU
meillo@8 302 I believe that mmh should be perfectly suited for modern emailing,
meillo@8 303 out-of-the-box.
meillo@8 304 .BU
meillo@8 305 I care less about compatibility and more about conceptionally elegant
meillo@8 306 approaches.
meillo@8 307 .BU
meillo@8 308 I care for general, clear, and simple concepts.
meillo@8 309 .BU
meillo@8 310 I like to create an of-one-style email system. It should feel like
meillo@8 311 cast as one.
meillo@8 312 .BU
meillo@8 313 I plan to remove any optimizations that rises obscurity, unless it
meillo@8 314 appears to be neccessary to make mmh usable at all.
meillo@8 315
meillo@27 316 .U2 "Work to do
meillo@8 317 .BU
meillo@27 318 Remove the MTA and MRA facilities. Mmh shall concentrate on the MUA
meillo@8 319 task. Mail shall enter mmh's mail storage via the system mail drop
meillo@8 320 and it shall leave mmh via the local \fLsendmail\fP command.
meillo@8 321 .BU
meillo@8 322 Remove any further functions that are not related to mmh's main task.
meillo@8 323 Bulletin board support is on example. Also remove support for ancient
meillo@8 324 technologies, like hardcopy terminals.
meillo@8 325 .BU
meillo@8 326 Refactor the source code to meet modern style criteria. Use
meillo@8 327 standardized library functions when possible.
meillo@8 328 .BU
meillo@8 329 Replace performance optimizations by clear and readable code.
meillo@8 330 .BU
meillo@8 331 Reduce the feature set to the commonly used one, removing
meillo@8 332 corner-cases. Set sane default values.
meillo@8 333 .BU
meillo@8 334 Add better attachment support. Add support for digital signatures and
meillo@8 335 encryption.
meillo@8 336 .BU
meillo@8 337 Merge \fLshow\fP and \fLmhshow\fP into one single mail display program.
meillo@8 338 Integrate MIME support deeper and more natural into MH.
meillo@8 339 .BU
meillo@8 340 Provide a ready-to-use setup out-of-the-box.
meillo@27 341
meillo@27 342
meillo@27 343 .H1 "Goals of this Thesis
meillo@27 344
meillo@27 345 .U2 "Methods
meillo@27 346 .P
meillo@27 347 foo