Spending on storage has jumped 10 percent in the past year as companies add more capacity to their networks, according to IDC.

Worldwide revenue for external disk storage systems rose to $4.3 billion in the third quarter of 2006, a 9.9 percent increase compared to the same period last year, said the analyst firm.

This is the 14th consecutive quarter of storage revenue growth, a trend IDC attributes to more companies buying storage because of the demand to save more data, and to existing customers buying larger capacity systems. "There is definitely a bump in the quarter on the systems side," said Brad Nisbet, manager of IDC's Storage Systems Program.

Sales growth has been particularly strong for mid-range systems while flat for high-end systems, Nisbet said. While the cost per megabyte of storage has continued to decline, the average selling price of systems has continued to rise because enterprises are buying larger and larger capacity storage.

The market share rankings of the top storage vendors were unchanged however. EMC kept the number one spot with a 21.4 percent share on an 18 percent increase in revenue over the year-ago quarter to $927 million. HP ranked second with a 17.6 percent share on only a modest 1.8 percent revenue increase to $760 million.

Third place went to IBM, with a 13.7 percent share. Dell, which sells co-branded Dell/EMC storage, ranked fourth with eight percent, and Hitachi Data Systems was fifth place with 7.9 percent.

The entire disk storage systems market grew 7.9 percent to $6.186 billion.