It's about four times as much as an iPod.
In other words, 604 gigabytes is 3.77 times the amount of an iPod, and the amount of an iPod is 0.265 times that amount.(a.k.a. Apple iPod) (2010 figures; for iPod classic, sixth generation)
It's about one-tenth as much as Watson.
In other words, 604 gigabytes is 0.15 times the amount of Watson, and the amount of Watson is 6.7 times that amount.(data store only)
Watson, the IBM supercomputer famous for competing against humans on the televised trivia game show Jeopardy!, utilizes 4,100 gigabytes of variously-structured data to formulate answers. While "thinking", Watson processes about 500 gigabytes of data per second.
It's about eleven times as much as Wikipedia.
In other words, the amount of Wikipedia is 0.091 times 604 gigabytes.(2009 figures) (all languages)
As of 2009, Wikipedia held 53 gigabytes (gB) of publicly written and edited encyclopedia articles on 14.5 million subjects as well as associated commentary and discussion. Wikipedia is among the ten most popular websites on the Internet and the only non-profit entity in that group.
It's about one-tenth as much as a Gap, Inc. Customer Database.
In other words, the amount of a Gap, Inc. Customer Database is 10 times 604 gigabytes.(a.k.a. The GAP Companies, a.k.a. Gap) (2012 figures)
The GAP Inc., the corporate parent of GAP store, Old Navy, and Banana Republic, has accumulated over 7,000 gigabytes of data on almost a billion customers. The GAP, Inc remains the largest apparel retailer in the United States and was the largest in the world from the mid-1990s until about 2008.
It's about twelve times as much as a Blu-ray Disc.
In other words, the amount of a Blu-ray Disc is 0.083 times 604 gigabytes.(a.k.a. BD) (dual-layer; Blu-ray disc)
It's about one-seventieth as much as The Amazon.com's databases.
In other words, 604 gigabytes is 0.0139392 times the amount of The Amazon.com's databases, and the amount of The Amazon.com's databases is 71.7401 times that amount.(largest databases only; 2005 figures)
It's about one-one-hundredth as much as The Google Earth database.
In other words, 604 gigabytes is 0.00837 times the amount of The Google Earth database, and the amount of The Google Earth database is 119 times that amount.(2006 figures) (raw imagery and indexes storage)