Re:...why not tapes? (Score 2, Interesting)

The reason for not using tapes is exactly because of the compression. The time it takes to compress that data and then send the data to the tape takes a lot of time. That same process would have to be repeated on the other end.

Besides, using HDD for transfer means immediate access to the same data on the other end with speeds that are unmatched with tape backup systems. It might also be worthy to note that data sets that large usually are stored on large RAID systems like this one from LSI Logic, http://www.lsilogic.com/storage_home/products_home /external_raid/6998_storage_system/index.html, and are not installed into a computer like you may be thinking. It provides unmatched speed and reliability. A single rack system can sustain 1,600 MB of transfer to attached hosts, which is how Google will probably use it anyway. I highly doubt a single computer will be looking at that much information.