HP's sales were down 6.3 percent for the year; Dell was fastest growing vendor EMC overtook Hewlett-Packard to become the top seller of external disk-based storage systems in 2004, according to IDC research released Friday.With just under $3 billion in revenue, up 18.4 percent from 2003, EMC had 21.1 percent of the market when measured by revenue. HP’s sales were $2.6 billion, down 6.3 percent year-over-year, giving it an 18.7 percent share of the market.“This is the first time since HP acquired Compaq that EMC has come back to overtake external storage,” said Brad Nisbet, a program manager with IDC. “EMC is firing on all cylinders.” IBM and Hitachi Data Systems were ranked third and fourth for the year, with sales of $1.8 billion and $1.2 billion, respectively. Dell, ranked fifth, was the fastest growing vendor of external storage systems for the year. Dell’s revenue was $994 million, up 18.7 percent from its 2003 total.Overall, sales of external disk-based storage systems were up 4.7 for the year, totalling $14.2 billion, but that growth slowed to less than 1 percent during the fourth quarter. IBM, in particular, had a poor finish to 2004, with fourth-quarter revenue dropping 20.3 percent from its 2003 results.IBM’s poor showing was caused by delays in shipping the DS6000 and DS8000 storage systems, Nisbet said. “They announced some new products on their high end and they weren’t ready,” he said. “Their customers are either waiting for Q1 availability or it stands to reason that EMC benefitted from that delay.” The DS6000 and DS8000 were unveiled in October but have only now begun ramping up to volume shipments, according to IBM.EMC and Dell remained the rising stars in the space with Q4 revenue of $844 million and $276 million, respectively. EMC’s revenue was up 13.4 percent from its 2003 total, and Dell’s rose even faster, by 15.2 percent. The two companies have collaborated the CX300 and AX100 storage systems, which are sold by both EMC and Dell.EMC’s $844 million in sales put it on top for the fourth quarter. HP and IBM were second and third for the quarter, with fourth-quarter revenue of $745 million and $504 million, respectively. The worldwide market for all disk-based storage, which includes storage systems shipped inside of servers, was dominated by HP and IBM. For the full year, in which $20.8 billion worth of disk-based storage was sold, HP had sales of $4.9 billion, or 23.6 percent of the market. IBM’s revenue was $4.3 billion, giving Big Blue 20.6 percent market share. Data Management