Zu ungenaue Dokumentation von Software-Anforderungen kann enorme Schäden verursachen


Anforderungen an unternehmenskritische Software müssen schriftlich, genau und vollständig dokumentiert sein.

Welch gewaltiger Schaden entstehen kann, wenn man das nicht beherzigt, zeigen die folgenden beiden Beispiele:

  • The Mars Climate Orbiter space probe failed to land on Sep 23, 1999, because its thruster control software was based on English units while the team responsible for adjusting its trajectory was using the metric system!
     
  • A few months later, the Mars Polar Lander also experienced a setback during its landing. It was still 40 metres above its final landing point when its feet deployed, as expected, but the software interpreted it as an imminent event. As a result, the computer shut down the descent engines, leading to an abrupt crash and total loss of both mission and hardware. System engineers had advised the software developers to not rely on the transient signal from the legs of the lander as they were deploying but, apparently, they failed to document this information in the software specifications.

Quelle: Software Quality Issues, 22 Jun 2015, by Claude Y. Laporte

Beide Beispiele zeigen klar und deutlich, dass keine Anforderung

  • als selbstverständlich gelten
  • oder auch nur undokumentiert bleiben darf.

Es reicht auf keinen Fall, Anforderungen nur mündlich zu kommunizieren — schon allein deswegen nicht, weil später hinzukommende Tester sie dann ja nicht kennen und deswegen auch nicht gezielt verifi­zie­ren werden.
 

Advertisements
Post a comment or leave a trackback: Trackback URL.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: