Mercurial > docs > unix-phil
annotate unix-phil.ms @ 2:fbd7baf6a61f
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| author | meillo@marmaro.de |
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| date | Fri, 05 Feb 2010 16:40:51 +0100 |
| parents | 9b555c009f19 |
| children | aebbe3e76f5e |
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1 .\".if n .pl 1000i |
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| 1 | 6 .\".nr PI 0 |
| 7 .\".if t .nr PD .5v | |
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| 19 .. | |
| 20 .ds [. \ [ | |
| 21 .ds .] ] | |
| 1 | 22 .\"---------------------------------------- |
| 0 | 23 .TL |
| 24 Why the Unix Philosophy matters | |
| 25 .AU | |
| 26 markus schnalke <meillo@marmaro.de> | |
| 27 .AB | |
| 1 | 28 .ti \n(.iu |
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29 This paper discusses the importance of the Unix Philosophy in software design. |
| 0 | 30 Today, few software designers are aware of these concepts, |
| 31 and thus most modern software is limited and does not use software leverage. | |
| 32 Knowing and following the tenets of the Unix Philosophy makes software more valuable. | |
| 33 .AE | |
| 34 | |
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35 .if t .2C |
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36 |
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37 .FS |
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38 .ps -1 |
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39 This paper was prepared for the seminar ``Software Analysis'' at University Ulm. |
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40 Mentor was professor Schweiggert. 2010-02-05 |
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41 .br |
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42 You may get this document from my website |
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43 .CW \s-1http://marmaro.de/docs |
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44 .FE |
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45 |
| 0 | 46 .NH 1 |
| 47 Introduction | |
| 48 .LP | |
| 49 Building a software is a process from an idea of the purpose of the software | |
| 50 to the finished program. | |
| 51 No matter \fIhow\fP the process is run, two things are common: | |
| 52 the initial idea and the release. | |
| 53 But the the process inbetween can be of any shape. | |
| 54 The time of release and the maintainance work after the release are ignored here, for the moment. | |
| 1 | 55 .PP |
| 0 | 56 The process of building splits mainly in two parts: |
| 57 the planning of what and how to build, and implementing the plan by writing code. | |
| 58 This paper focuses on the planning \(en the design \(en of software. | |
| 59 The here discussed ideas may be applied to any development process. | |
| 60 Though the Unix Philosphy does recommend how the software development process should look like, | |
| 61 this shall not be of matter here. | |
| 62 Similar, the question of how to write the code is out of focus. | |
| 1 | 63 .PP |
| 64 This paper discusses the connection between software design and the Unix Philosphy. | |
| 65 Software design is the work between the requirements and the plan of how the internals and externals | |
| 66 of the software should look like. | |
| 67 However, the term ``Unix Philosophy'' was used but not explained yet. | |
| 68 .PP | |
| 69 The Unix Philosophy is the essence of how the Unix operating system and its toolchest was designed. | |
| 70 It is no limited set of rules, but what people see what is common to typical Unix software. | |
| 71 Several people stated their view on the Unix Philosophy. | |
| 72 Best known are: | |
| 73 .IP \(bu | |
| 74 Doug McIlroy's summary: ``Write programs that do one thing and do it well.'' | |
| 75 .[ | |
| 76 %A M. D. McIlroy | |
| 77 %A E. N. Pinson | |
| 78 %A B. A. Taque | |
| 79 %T UNIX Time-Sharing System Forward | |
| 80 %J The Bell System Technical Journal | |
| 81 %D 1978 | |
| 82 %V 57 | |
| 83 %N 6 | |
| 84 %P 1902 | |
| 85 .] | |
| 86 .IP \(bu | |
| 87 Mike Gancarz' book ``The UNIX Philosophy''. | |
| 88 .[ | |
| 89 %A Mike Gancarz | |
| 90 %T The UNIX Philosophy | |
| 91 %D 1995 | |
| 92 %I Digital Press | |
| 93 .] | |
| 94 .IP \(bu | |
| 95 Eric S. Raymond's book ``The Art of UNIX Programming''. | |
| 96 .[ | |
| 97 %A Eric S. Raymond | |
| 98 %T The Art of UNIX Programming | |
| 99 %D 2003 | |
| 100 %I Addison-Wesley | |
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101 %O .CW \s-1http://www.faqs.org/docs/artu/ |
| 1 | 102 .] |
| 0 | 103 .LP |
| 1 | 104 These different views on the Unix Philosophy have much in common. |
| 105 Especially, the main concepts are seen by all of them. | |
| 106 But there are also points on which they differ. | |
| 107 This only underlines what the Unix Philosophy is: | |
| 108 A retrospective view on the main concepts of Unix software; | |
| 109 especially those that were sucessful and unique to Unix. | |
| 110 .PP | |
| 111 Before we will have a look at concrete concepts, | |
| 112 we discuss why software design is important | |
| 113 and what problems bad design introduces. | |
| 0 | 114 |
| 115 | |
| 116 .NH 1 | |
| 117 Importance of software design | |
| 118 .LP | |
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119 Why should we design software at all? |
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120 It should be general knowledge, that a bad plan is better than no plan. |
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121 As stated earlier in this document, the process of building a software |
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122 means going from an idea to a release. |
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123 The development process tells how to get from the idea to the release. |
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124 Software design tells how the built software should look like. |
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125 .PP |
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126 It is not enough that the released software offers all requested functionality. |
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127 It is a misbelief that only function matters. |
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128 Building a software the first time is only a small part of the overall work. |
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129 The larger part begins when the software is released for the first time |
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130 \(en maintainance and extending work.. |
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131 This part soon covers more time than the time which was needed to build the software the first time. |
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132 .\" cf. brooks? |
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133 .PP |
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134 The extendability and maitainability of a software highly depends on its design. |
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135 Good design eases these tasks much. |
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136 Bad design, in contrast, requires much more effort for maintaining and |
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137 extending the software. |
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138 Developers should, for their own best, have maintainability and extendability in mind |
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139 when they design the software. |
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140 .PP |
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141 Users of the software do not care about maintainability and extendability, |
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142 at least not directly. |
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143 They care about usability and flexibility. |
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144 They want the software to directly solve their problems. |
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145 They want to be able to to use all its functions if they learned a few of them. |
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146 They want to use the software for similar tasks. |
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147 Software is successful if users enjoy using it. |
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148 Good software design can offer great flexibility and usability. |
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149 .PP |
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150 Good design matters for developers \fIand\fP for users. |
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151 Hence both groups should care about good software design. |
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152 Bad design limits the software in some way. |
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153 It may still provide all requested function, but it will have worse quality, |
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154 and thus require more work effort for developers or frustrate users. |
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155 .PP |
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156 Good software design is to the implementation like data structures are to algorithms |
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157 \(en if you get the former right, then you do not need to care about the latter, |
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158 it will simply go the right way. |
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159 .\" cf. ??? ``good data, bad algos'' |
| 0 | 160 |
| 161 | |
| 162 | |
| 163 | |
| 164 .NH 1 | |
| 165 The Unix Philosophy | |
| 166 | |
| 167 .NH 2 | |
| 168 what it is | |
| 169 .LP | |
| 170 definitions by McIlroy, Gancarz, ESR (maybe already in the intro) | |
| 171 .LP | |
| 172 cf. unix tool chain | |
| 173 .LP | |
| 174 enabler pipe | |
| 175 | |
| 176 .NH 2 | |
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177 Architecture |
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178 .LP |
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179 the most important design decision. |
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180 |
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181 the topic here |
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182 |
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183 .NH 2 |
| 0 | 184 Interface architecture |
| 185 .LP | |
| 186 standalone vs. tool chain | |
| 187 .LP | |
| 188 software leverage | |
| 189 .LP | |
| 190 possiblities | |
| 191 | |
| 192 .NH 2 | |
| 193 Results | |
| 194 .LP | |
| 195 The unix phil is an answer to the sw design question | |
| 196 .LP | |
| 197 tool chains empower the uses of sw | |
| 198 | |
| 199 .NH 1 | |
| 200 Case study: nmh | |
| 201 | |
| 202 .NH 2 | |
| 203 History | |
| 204 .LP | |
| 205 MH, nmh. | |
| 206 They are old. | |
| 207 | |
| 208 .NH 2 | |
| 209 Contrasts to similar sw | |
| 210 .LP | |
| 211 vs. Thunderbird, mutt, mailx, pine | |
| 212 .LP | |
| 213 flexibility, no redundancy, use the shell | |
| 214 | |
| 215 .NH 2 | |
| 216 Gains of the design | |
| 217 .LP | |
| 218 | |
| 219 .NH 2 | |
| 220 Problems | |
| 221 .LP | |
| 222 | |
| 223 .NH 1 | |
| 224 Case study: uzbl | |
| 225 | |
| 226 .NH 2 | |
| 227 History | |
| 228 .LP | |
| 229 uzbl is young | |
| 230 | |
| 231 .NH 2 | |
| 232 Contrasts to similar sw | |
| 233 .LP | |
| 234 like with nmh | |
| 235 .LP | |
| 236 addons, plugins, modules | |
| 237 | |
| 238 .NH 2 | |
| 239 Gains of the design | |
| 240 .LP | |
| 241 | |
| 242 .NH 2 | |
| 243 Problems | |
| 244 .LP | |
| 245 broken web | |
| 246 | |
| 247 .NH 1 | |
| 248 Final thoughts | |
| 249 | |
| 250 .NH 2 | |
| 251 Quick summary | |
| 252 .LP | |
| 253 good design | |
| 254 .LP | |
| 255 unix phil | |
| 256 .LP | |
| 257 case studies | |
| 258 | |
| 259 .NH 2 | |
| 260 Why people should choose | |
| 261 .LP | |
| 262 Make the right choice! | |
| 263 | |
| 264 .nr PI .5i | |
| 265 .rm ]< | |
| 266 .de ]< | |
| 267 .LP | |
| 268 .de FP | |
| 269 .IP \\\\$1. | |
| 270 \\.. | |
| 271 .rm FS FE | |
| 272 .. | |
| 273 .SH | |
| 274 References | |
| 275 .[ | |
| 276 $LIST$ | |
| 277 .] | |
| 278 .wh -1p |