Едно от значенията според WIKI -
ETA is also used metaphorically in situations where nothing actually moves physically, as in describing the time estimated for a certain task to complete (e.g. work undertaken by an individual; a computation undertaken by a computer program; or a process undertaken by an organization). The associated term is "estimated time of accomplishment", which may be a backronym.[citation needed] For example, Bittorrent clients specify ETA as the expected time remaining for a file to completely download as 1d4h (1 day and 4 hours), 1w2d (1 week and 2 days), etc.
http://en.wikipedia.org/wiki/Estimated_time_of_arrival