[On May 14, 2010, the following edits were made to this post, originally published on March 24, 2009]
Many organizations need to preserve documents for a long period of time, for example, decades or more. The challenge with this need is that hardware and software technologies continually evolve and may become incompatible with the documents preserved or archived. Fortunately, the International Organization for Standardization (ISO) defined a standard a number of years ago, for long term document archival based on the PDF format called PDF/A or PDF/A-1 (ISO 19005-1:2005). The ISO worked with representatives from government, industry, academia and Adobe to define this PDF/A standard.