Sun Microsystems Inc. bulked up the capacity and improved the performance Wednesday of disk drives used in its midrange storage systems.

Sun storage customers will now be able to fit disks of up to 181G bytes into the company’s StorEdge 3900 and StorEdge 6900 systems. Sun will also ship 36G-byte drives with speeds of 15,000 RPM (revolutions per minute), said Steve Guzowski, group marketing manager for network storage at Sun. These Sun drives previously featured a top speed of 10,000 RPM.

The larger 181G-byte disks mark a jump over previous 73G-byte disks and will double the storage capacity of the midrange systems from 11T bytes to more than 29T bytes in a maximum configuration.

Customers that typically look for large-capacity drives include government agencies, insurance firms and educational institutions, Guzowski said.

Other companies that have to process transactions quickly, such as credit card companies, are likely candidates for the new 15,000 RPM drives.

Customers will pay up to 10 per cent more for StorEdge 3900 and StorEdge 6900 systems with the faster drives and more for the larger capacity drives as well , Guzowski said. The price will vary, however, depending on what type of configuration a customer chooses.