Calculation model for costs of (digital) storage

Goal This is a spreadsheet that can help understand the different components of the costs of storing large amounts of digital data for an extended time period. It is not meant to be an accurate representation of a the real costs, but it is good enough to learn to understand why an (institutional) "Storage Service" is much more expensive than "Buying some hard drives". This tool is suitable for self-education, but can also be used by research support in a discussion with a researcher during the creation of a data management budget. The spreadsheet is given here as an Excel format file, and it is also available as a google spreadsheet under https://docs.google.com/spreadsheets/d/1IGW0cA549Nn21HV5139B1v1ioRNDej1PfjqmBQ0kjNM/copy Usage The spreadsheet consists of 3 different fields. The leftmost field contains information about a data set that needs to be preserved or made available to a user community. There are a number of fields marked in yellow where data needs to be filled in in free form (e.g. the volume of data), or a management aspect of the data set must be selected from a set of options (e.g. is it open / closed / sensitive data). Based on the information given in these fields, the spreadsheet will calculate the costs of the storage in the center field. Also, important considerations may be shown as red text in the bottom of the left field. The rightmost field contains underlying data for the calculations. Values here are things like the price of hard disk drives per TB, the price of electrical power, and the storage speed of tape technology. Updating values in this field may help to get a more up to date and localised cost calculation. Acknowledgements Thanks to several of my colleagues for their input on this model and fruitful discussions