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		| Paper: | 
		IRAF: Lessons for Project Longevity | 
	 
	
		| Volume: | 
		461, Astronomical Data Analysis Software and Systems XXI | 
	 
	
		| Page: | 
		595 | 
	 
	
		| Authors: | 
		Fitzpatrick, M. | 
	 
	
	
		| Abstract: | 
		Although sometimes derided as a product of the 80's (or more
 generously, as a legacy system), the fact that IRAF remains a
 productive work environment for many astronomers today is a testament to one
 of its core design principles, portability. This idea has meaning beyond a
 survey of platforms in use at the peak of a project's active development;
 for true longevity, a project must be able to weather completely unimagined
 OS, hardware, data, staffing and political environments. A lack of
 attention to the broader issues of portability, or the true lifespan of
 a software system (e.g.  archival science may extend for years beyond
 a given mission, upgraded or similar instruments may be developed that
 require the same reduction/analysis techniques, etc) might require costly
 new software development instead of simple code re-use. Additionally,
 one under-appreciated benefit to having a long history in the community is
 the trust that users have established in the science results produced by
 a particular system. However a software system evolves architecturally,
 preserving this trust (and by implication, the applications themselves)
 is the key to continued success.
 
 In this paper, we will discuss how the system architecture has allowed IRAF
 to navigate the many changes in computing since it was first released.
 It is hoped that the lessons learned can be adopted by software systems
 being built today so that they too can survive long enough to one day earn
 the distinction of being called a legacy system. | 
	 
	
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