3.5” Enterprise Hard Drive Development Analyzed

2005: Ultrastar 15K147 (147GB)

The Hitachi Ultrastar 15K147 was one of the first SAS 3 Gb/s hard drives made available back in 2005, although hard drives working at a 15,000 RPM spindle speed were introduced a few years earlier. Our sample is dated June 2005. The peak capacity of this hard drive family is 147GB, but Hitachi also offered 36GB and 73GB capacity points. The product line included drives with Ultra320 SCSI and 2/4 Gb/s Fibre Channel interfaces, as well as the SAS 3 Gb/s drives we received. The drives are equipped with 16MB buffer memory, and they operate between 5° and 55° Celsius. The latter spec hasn’t changed even in the latest drive generations, but there are some hard drive families supporting a wider operating temperature range.

All of the following Ultrastar 15K families utilize up to four rotating platters to achieve their maximum capacities, while the Ultrastar 15K147 still utilizes up to five platters to realize its 147GB capacity. The 73GB models employ three platters, and two are necessary for the 36GB models.

This 147GB drive delivers up to 91 MB/s read throughput, which is about as much as an average desktop hard drive running at 5,400 RPM can serve up today. However, the 6.2 ms average read access time is still unmatched by desktop drives and only the fastest 15,000 RPM drives can actually beat it. The only way to get quicker access and improved I/O performance is to opt for SSDs.