What Should We Collect to Preserve the History of Software?

@article{Shustek2006WhatSW,
  title={What Should We Collect to Preserve the History of Software?},
  author={Leonard J. Shustek},
  journal={IEEE Annals of the History of Computing},
  year={2006},
  volume={28},
  pages={112-111}
}
Software is more than cards, tapes and disks; it is the meaning of the bits that they contain. To properly preserve the history of computing, we must preserve the software code, especially the source code, for analysis by future historians.