Big Databases

InformationWeek last month had a column mentioning who/what companies that have the biggest database in their servers. The following is the top ten commercial databases with the gigantic size:

1. Yahoo, 100.4 TB. Platform: Unix
2. AT&T Lab, 93.9 TB. Platform: Unix
3. KT IT-Group, 49.4 TB. Platform: Unix
4. AT & T Lab, 26.7 TB. Platform: Unix
5. LGR-Cingular, 25.2 TB, Platform: Unix
6. Amazon.com, 24.8 TB, Platform: Linux
7. Anonymous, 19.7 TB. Platform: Unix
8. Unisys, 19.5 TB. Platform: Windows
9. Amazon.com, 18.6 TB. Platform: Linux
10. Nielsen Media, 17.7 TB. Platform: Unix

It is not wondering to see Yahoo is in the top list, because they provide 2 GB/user. If there is 20 million users in US itself, it is 2 GB * 20 million = 40,000,000 GB = 40,000 TB. So I still don't understand why it says only 100 TB.
Or, may be it is has less than 20 million users in US? Likely.

With current commodity hard disks available in the market, a 400 GB HD can be bought at around $300 (I just checked shopping.com, it actually costs less than that), so with 3 drives we could get 1.2 TB storage space with cost only $900. To get 120 TB, it costs only $90,000.

To see the full detail, see www.wintercorp.com