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