Mercurial > docs > diploma

comparison thesis/tex/4-MasqmailsFuture.tex @ 191:74a6cbdc7255

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
new book and small changes
author meillo@marmaro.de
date Tue, 30 Dec 2008 13:34:08 +0100
parents 79803ad327ca
children b80438534651
comparison
equal deleted inserted replaced
190:b1d067a532de 191:74a6cbdc7255
62 \subsubsection*{Reliability} 62 \subsubsection*{Reliability}
63 Reliability is the second essential quality property for an \MTA. Mail, for which the \MTA\ took responsibility, must never get lost. The \MTA\ must not be the cause of any mail loss, no matter what happens. Unreliable \mta{}s are of no value. 63 Reliability is the second essential quality property for an \MTA. Mail, for which the \MTA\ took responsibility, must never get lost. The \MTA\ must not be the cause of any mail loss, no matter what happens. Unreliable \mta{}s are of no value.
64 64
65 65
66 \subsubsection*{Robustness} 66 \subsubsection*{Robustness}
67 Being robust means handling errors properly. Small errors may get tolerated, large errors may kill a process, to get restarted afterwards. Log messages should be written in every case. Robust software does not need a special environment, it creates the right environment itself. \person{Raymond}'s \name{Rule of Robustness} and his \name{Rule of Repair} are good descriptions.\cite[page~18--21]{raymond03} 67 Being robust means handling errors properly. Small errors may get tolerated, large errors may kill a process, to get restarted afterwards. Log messages should be written in every case. Robust software does not need a special environment, it creates the right environment itself. \person{Raymond}'s \name{Rule of Robustness} and his \name{Rule of Repair} are good descriptions.\cite[pages~18--21]{raymond03}
68 68
69 69
70 \subsubsection*{Extendability} 70 \subsubsection*{Extendability}
71 Modern needs like large messages demand for more efficient mail transport through the net. Aswell is a final solution needed to defeat the spam problem. New mail transport protocols seem to be the only good solutions for both problems. They also can improve reliability, authentication, and verification issues. \masqmail\ should be able to support new mail transfer protocols as they appear and are used. 71 Modern needs like large messages demand for more efficient mail transport through the net. Aswell is a final solution needed to defeat the spam problem. New mail transport protocols seem to be the only good solutions for both problems. They also can improve reliability, authentication, and verification issues. \masqmail\ should be able to support new mail transfer protocols as they appear and are used.
72 %fixme: like old sendmail, but not too much like it 72 %fixme: like old sendmail, but not too much like it
73 73
74 \subsubsection*{Maintainability} 74 \subsubsection*{Maintainability}
75 Maintaining software takes much time and effort. \person{Spinellis} measures ``40\% to 70\% of the effort that goes into a software system is expended after the system is written first time.''\cite[page~1]{spinellis03} This is maintaining work. Hence making software good to maintain is effort that will become invalueable afterwards. 75 Maintaining software takes much time and effort. \person{Spinellis} measures ``40\,\% to 70\,\% of the effort that goes into a software system is expended after the system is written first time.''\cite[page~1]{spinellis03} This is maintaining work. Hence making software good to maintain is effort that will become invalueable afterwards.
76 76
77 77
78 \subsubsection*{Testability} 78 \subsubsection*{Testability}
79 Good testability make maintainance easier, because functionality is directly verifiable when changes are done, thus removing the uncertaintay. Modularized software makes testing easier, because parts can be testet without external influences. 79 Good testability make maintainance easier, because functionality is directly verifiable when changes are done, thus removing the uncertaintay. Modularized software makes testing easier, because parts can be testet without external influences.
80 80
81 81
82 \subsubsection*{Performance} 82 \subsubsection*{Performance}
83 Also called ``efficiency''. Software requiring few time and few resources is nice. But as performance improvements are in contrast to many other quality poperties (reliability, maintainability, usability, capability \cite[page~5]{kan03}), japardizing them to gain some more performance should not be done. \person{Kernighan} and \person{Pike} state clear: ``[T]he first principle of optimization is \emph{don't}.''\cite{kernighan99} 83 Also called ``efficiency''. Software requiring few time and few resources is nice. But as performance improvements are in contrast to many other quality poperties (reliability, maintainability, usability, capability \cite[page~5]{kan03}), japardizing them to gain some more performance should not be done. \person{Kernighan} and \person{Pike} state clear: ``[T]he first principle of optimization is \emph{don't}.''\cite[page~165]{kernighan99}
84 84
85 The merge of communication hardware and the move of email services from providers to homes, demands smaller and more resource-friendly software. The amount of mail will be lower, even if much more mail will be sent. More important will be the energy consumption and heat emission. These topics increased in relevance during the past years and they are expected to become more central. \masqmail\ is not a program to be used on large servers, but to be used on small devices. Thus focusing on energy and heat, not on performance, is the direction to go. 85 The merge of communication hardware and the move of email services from providers to homes, demands smaller and more resource-friendly software. The amount of mail will be lower, even if much more mail will be sent. More important will be the energy consumption and heat emission. These topics increased in relevance during the past years and they are expected to become more central. \masqmail\ is not a program to be used on large servers, but to be used on small devices. Thus focusing on energy and heat, not on performance, is the direction to go.
86 86
87 87
88 \subsubsection*{Availability} 88 \subsubsection*{Availability}