meillo@0: .if n .pl 1000i meillo@0: .de XX meillo@0: .pl 1v meillo@0: .. meillo@0: .em XX meillo@1: .\".nr PI 0 meillo@1: .\".if t .nr PD .5v meillo@1: .\".if n .nr PD 1v meillo@0: .nr lu 0 meillo@0: .de CW meillo@0: .nr PQ \\n(.f meillo@0: .if t .ft CW meillo@0: .ie \\$1 .if n .ul 999 meillo@0: .el .if n .ul 1 meillo@0: .if t .if !\\$1 \&\\$1\f\\n(PQ\\$2 meillo@0: .if n .if \\n(.$=1 \&\\$1 meillo@0: .if n .if \\n(.$>1 \&\\$1\c meillo@0: .if n .if \\n(.$>1 \&\\$2 meillo@0: .. meillo@0: .ds [. \ [ meillo@0: .ds .] ] meillo@1: .\"---------------------------------------- meillo@0: .TL meillo@0: Why the Unix Philosophy matters meillo@0: .AU meillo@0: markus schnalke meillo@1: .AI meillo@1: .ce 0 meillo@1: University Ulm meillo@0: .AB meillo@1: .ti \n(.iu meillo@0: This term paper discusses the importance of the Unix Philosophy in software design. meillo@0: Today, few software designers are aware of these concepts, meillo@0: and thus most modern software is limited and does not use software leverage. meillo@0: Knowing and following the tenets of the Unix Philosophy makes software more valuable. meillo@0: .AE meillo@0: meillo@0: .2C meillo@0: .NH 1 meillo@0: Introduction meillo@0: .LP meillo@0: Building a software is a process from an idea of the purpose of the software meillo@0: to the finished program. meillo@0: No matter \fIhow\fP the process is run, two things are common: meillo@0: the initial idea and the release. meillo@0: But the the process inbetween can be of any shape. meillo@0: The time of release and the maintainance work after the release are ignored here, for the moment. meillo@1: .PP meillo@0: The process of building splits mainly in two parts: meillo@0: the planning of what and how to build, and implementing the plan by writing code. meillo@0: This paper focuses on the planning \(en the design \(en of software. meillo@0: The here discussed ideas may be applied to any development process. meillo@0: Though the Unix Philosphy does recommend how the software development process should look like, meillo@0: this shall not be of matter here. meillo@0: Similar, the question of how to write the code is out of focus. meillo@1: .PP meillo@1: This paper discusses the connection between software design and the Unix Philosphy. meillo@1: Software design is the work between the requirements and the plan of how the internals and externals meillo@1: of the software should look like. meillo@1: However, the term ``Unix Philosophy'' was used but not explained yet. meillo@1: .PP meillo@1: The Unix Philosophy is the essence of how the Unix operating system and its toolchest was designed. meillo@1: It is no limited set of rules, but what people see what is common to typical Unix software. meillo@1: Several people stated their view on the Unix Philosophy. meillo@1: Best known are: meillo@1: .IP \(bu meillo@1: Doug McIlroy's summary: ``Write programs that do one thing and do it well.'' meillo@1: .[ meillo@1: %A M. D. McIlroy meillo@1: %A E. N. Pinson meillo@1: %A B. A. Taque meillo@1: %T UNIX Time-Sharing System Forward meillo@1: %J The Bell System Technical Journal meillo@1: %D 1978 meillo@1: %V 57 meillo@1: %N 6 meillo@1: %P 1902 meillo@1: .] meillo@1: .IP \(bu meillo@1: Mike Gancarz' book ``The UNIX Philosophy''. meillo@1: .[ meillo@1: %A Mike Gancarz meillo@1: %T The UNIX Philosophy meillo@1: %D 1995 meillo@1: %I Digital Press meillo@1: .] meillo@1: .IP \(bu meillo@1: Eric S. Raymond's book ``The Art of UNIX Programming''. meillo@1: .[ meillo@1: %A Eric S. Raymond meillo@1: %T The Art of UNIX Programming meillo@1: %D 2003 meillo@1: %I Addison-Wesley meillo@1: %O .CW \s-2http://www.faqs.org/docs/artu/ meillo@1: .] meillo@0: .LP meillo@1: These different views on the Unix Philosophy have much in common. meillo@1: Especially, the main concepts are seen by all of them. meillo@1: But there are also points on which they differ. meillo@1: This only underlines what the Unix Philosophy is: meillo@1: A retrospective view on the main concepts of Unix software; meillo@1: especially those that were sucessful and unique to Unix. meillo@1: .PP meillo@1: Before we will have a look at concrete concepts, meillo@1: we discuss why software design is important meillo@1: and what problems bad design introduces. meillo@0: meillo@0: meillo@0: .NH 1 meillo@0: Importance of software design meillo@0: .LP meillo@0: why design at all meillo@0: meillo@0: - for dev mainly: extendability and maintainability meillo@0: meillo@0: - for users: usability and flexibility (but you need to learn how to use it) meillo@0: meillo@0: no design and bad design limit the use of software meillo@0: meillo@0: .NH 2 meillo@0: Architecture meillo@0: .LP meillo@0: the most important design decision. meillo@0: meillo@0: the topic here meillo@0: meillo@0: .NH 1 meillo@0: The Unix Philosophy meillo@0: meillo@0: .NH 2 meillo@0: what it is meillo@0: .LP meillo@0: definitions by McIlroy, Gancarz, ESR (maybe already in the intro) meillo@0: .LP meillo@0: cf. unix tool chain meillo@0: .LP meillo@0: enabler pipe meillo@0: meillo@0: .NH 2 meillo@0: Interface architecture meillo@0: .LP meillo@0: standalone vs. tool chain meillo@0: .LP meillo@0: software leverage meillo@0: .LP meillo@0: possiblities meillo@0: meillo@0: .NH 2 meillo@0: Results meillo@0: .LP meillo@0: The unix phil is an answer to the sw design question meillo@0: .LP meillo@0: tool chains empower the uses of sw meillo@0: meillo@0: .NH 1 meillo@0: Case study: nmh meillo@0: meillo@0: .NH 2 meillo@0: History meillo@0: .LP meillo@0: MH, nmh. meillo@0: They are old. meillo@0: meillo@0: .NH 2 meillo@0: Contrasts to similar sw meillo@0: .LP meillo@0: vs. Thunderbird, mutt, mailx, pine meillo@0: .LP meillo@0: flexibility, no redundancy, use the shell meillo@0: meillo@0: .NH 2 meillo@0: Gains of the design meillo@0: .LP meillo@0: meillo@0: .NH 2 meillo@0: Problems meillo@0: .LP meillo@0: meillo@0: .NH 1 meillo@0: Case study: uzbl meillo@0: meillo@0: .NH 2 meillo@0: History meillo@0: .LP meillo@0: uzbl is young meillo@0: meillo@0: .NH 2 meillo@0: Contrasts to similar sw meillo@0: .LP meillo@0: like with nmh meillo@0: .LP meillo@0: addons, plugins, modules meillo@0: meillo@0: .NH 2 meillo@0: Gains of the design meillo@0: .LP meillo@0: meillo@0: .NH 2 meillo@0: Problems meillo@0: .LP meillo@0: broken web meillo@0: meillo@0: .NH 1 meillo@0: Final thoughts meillo@0: meillo@0: .NH 2 meillo@0: Quick summary meillo@0: .LP meillo@0: good design meillo@0: .LP meillo@0: unix phil meillo@0: .LP meillo@0: case studies meillo@0: meillo@0: .NH 2 meillo@0: Why people should choose meillo@0: .LP meillo@0: Make the right choice! meillo@0: meillo@0: .nr PI .5i meillo@0: .rm ]< meillo@0: .de ]< meillo@0: .LP meillo@0: .de FP meillo@0: .IP \\\\$1. meillo@0: \\.. meillo@0: .rm FS FE meillo@0: .. meillo@0: .SH meillo@0: References meillo@0: .[ meillo@0: $LIST$ meillo@0: .] meillo@0: .wh -1p