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Further minor improvements.
author markus schnalke <meillo@marmaro.de>
date Sun, 15 Jul 2012 19:46:35 +0200
parents 1fa5a74bf138
children d83ab437e3a6
comparison
equal deleted inserted replaced
223:1fa5a74bf138 224:b0e83cfde2bf
6 A selection of the work undertaken 6 A selection of the work undertaken
7 is described. 7 is described.
8 .P 8 .P
9 This discussion compares the present version of mmh with the state of 9 This discussion compares the present version of mmh with the state of
10 nmh at the time when the mmh project had started, i.e. fall 2011. 10 nmh at the time when the mmh project had started, i.e. fall 2011.
11 Recent changes in nmh are seldom part of the discussion. 11 Recent changes in nmh are rarely part of the discussion.
12 Sometimes they are mentioned in side notes.
13 .P 12 .P
14 For the reader's convenience, the structure of modern email systems 13 For the reader's convenience, the structure of modern email systems
15 is depicted in the following figure. 14 is depicted in the following figure.
16 It illustrates the path a message takes from sender to recipient. 15 It illustrates the path a message takes from sender to recipient.
17 16
47 (The dashed arrow in the figure represents the pull request.) 46 (The dashed arrow in the figure represents the pull request.)
48 .LP 47 .LP
49 The dashed boxes represent entities that usually reside on single machines. 48 The dashed boxes represent entities that usually reside on single machines.
50 The box on the lower left represents the sender's system. 49 The box on the lower left represents the sender's system.
51 The box on the upper left represents the first mail transfer node. 50 The box on the upper left represents the first mail transfer node.
52 The box on the upper right represents the transfer node responsible for the 51 The box on the upper right represents the transfer node responsible
53 destination address. 52 for the destination address.
54 The box on the lower right represents the recipient's system. 53 The box on the lower right represents the recipient's system.
55 Often, the boxes above the dotted line are servers on the Internet. 54 Often, the boxes above the dotted line are servers on the Internet.
56 Many mail clients, including nmh, include all of the components below 55 Many mail clients, including nmh, include all of the components below
57 the dotted line. 56 the dotted line.
58 This is not the case for mmh; it implements the MUA only. 57 This is not the case for mmh; it implements the MUA only.
190 Additionally, the best suiting programs can be chosen freely. 189 Additionally, the best suiting programs can be chosen freely.
191 .P 190 .P
192 As it had already been possible to use an external MSA and MRA, 191 As it had already been possible to use an external MSA and MRA,
193 why should the internal version not be kept for convenience? 192 why should the internal version not be kept for convenience?
194 .\" XXX commas correct? 193 .\" XXX commas correct?
195 Transfered to a different area, 194 Transfered to a different area, the question,
196 the question whether there is sense in having a fall-back pager in all 195 whether there is sense in having a fall-back pager in all
197 the command line tools, for the cases when 196 the command line tools for the cases when
198 .Pn more 197 .Pn more
199 or 198 or
200 .Pn less 199 .Pn less
201 are not available, appears to be ridiculous. 200 are not available, appears to be ridiculous.
202 Of course, MSAs and MRAs are more complex than text pagers 201 Of course, MSAs and MRAs are more complex than text pagers
226 Once, email had been small and simple. 225 Once, email had been small and simple.
227 At that time, 226 At that time,
228 .Pn /bin/mail 227 .Pn /bin/mail
229 had covered everything there was to email and still was small and simple. 228 had covered everything there was to email and still was small and simple.
230 Later, the essential complexity of email increased. 229 Later, the essential complexity of email increased.
231 (Essential complexity is the complexity defined by the problem itself.\& 230 (Essential complexity is the complexity defined by the problem itself
232 .[ [ 231 .[ [
233 brooks no silver bullet 232 brooks no silver bullet
234 .]]) 233 .]].)
235 Consequently, email systems grew. 234 Consequently, email systems grew.
236 RFCs started to introduce the concept of mail agents to separate the 235 RFCs started to introduce the concept of mail agents to separate the
237 various roles because they became more extensive and because 236 various roles because they became more extensive and because
238 new roles appeared. 237 new roles appeared.
239 As mail system implementations grew, parts of them were split off. 238 As mail system implementations grew, parts of them were split off.
2220 information on how to display the individual parts. 2219 information on how to display the individual parts.
2221 I adjusted 2220 I adjusted
2222 .Pn mhshow 's 2221 .Pn mhshow 's
2223 behavior to the modern view on the topic. 2222 behavior to the modern view on the topic.
2224 .P 2223 .P
2225 (One should note that this section completely ignores the original 2224 One should note that this section completely ignores the original
2226 .Pn show 2225 .Pn show
2227 program, because it was not capable to display MIME messages 2226 program, because it was not capable to display MIME messages
2228 and is no longer part of mmh. 2227 and is no longer part of mmh.
2229 .\" XXX ref to other section 2228 .\" XXX ref to other section
2230 Although 2229 Although
2231 .Pn mhshow 2230 .Pn mhshow
2232 was renamed to 2231 was renamed to
2233 .Pn show 2232 .Pn show
2234 in mmh, this section uses the name 2233 in mmh, this section uses the name
2235 .Pn mhshow , 2234 .Pn mhshow ,
2236 in order to avoid confusion.) 2235 in order to avoid confusion.
2237 .P 2236 .P
2238 In mmh, the basic idea is that 2237 In mmh, the basic idea is that
2239 .Pn mhshow 2238 .Pn mhshow
2240 should display a message in one single pager session. 2239 should display a message in one single pager session.
2241 Therefore, 2240 Therefore,