Data storage, which has typically offered refuge for tech firms battling tough economies, is finally feeling the effects of the spending crunch. This is the sobering message from technology research firm IDC, which says that quarterly storage revenue has slipped for the first time in more than five years. Recent years have seen an explosion in data, earning storage a reputation as one of the more recession-resistant parts of the tech sector, particularly compared to PCs and servers. This spelled good news for tech firms such as EMC ( EMC), NetApp ( NTAP), IBM ( IBM), and Hewlett-Packard ( HPQ), which could all count on solid storage growth. That's no longer the case, according to IDC, which saw total fourth-quarter revenue from disk storage systems plunge 5.9% year over year to $7.3 billion. "Because of the global economic crisis, the last quarter of 2008 was tough for the disk storage systems market," said Natalya Yezhkova, an IDC research manager, in a statement. IDC blamed weakness in server sales for the slump and noted that revenue from external disk systems declined 0.5% year over year, its first slip in more than five years. Clearly, there are few places for tech firms to hide in the current climate. "Previously, storage systems have been a safe haven, especially when you think about the growth that we expect in data volumes -- it's something like a factor of 10 every five years," says Jerry Luftman, distinguished professor at Stevens Institute of Technology in Hoboken, N.J. "This is the result of the recession and the fact that information systems organizations are being asked to hold back on purchases."